HackTool.Win32.IdleKMS.gen

Adversaries may abuse the at utility to perform task scheduling for initial or recurring execution of malicious code. The at utility exists as an executable within Windows, Linux, and macOS for scheduling tasks at a specified time and date. Although deprecated in favor of Scheduled Task’s schtasks in Windows environments, using at requires that the Task Scheduler service be running, and the user to be logged on as a member of the local Administrators group.

On Linux and macOS, at may be invoked by the superuser as well as any users added to the at.allow file. If the at.allow file does not exist, the at.deny file is checked. Every username not listed in at.deny is allowed to invoke at. If the at.deny exists and is empty, global use of at is permitted. If neither file exists (which is often the baseline) only the superuser is allowed to use at.(Citation: Linux at)

Adversaries may use at to execute programs at system startup or on a scheduled basis for Persistence. at can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM).

In Linux environments, adversaries may also abuse at to break out of restricted environments by using a task to spawn an interactive system shell or to run system commands. Similarly, at may also be used for Privilege Escalation if the binary is allowed to run as superuser via sudo.(Citation: GTFObins at)

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 to create a scheduled task.

The deprecated at utility could also be abused by adversaries (ex: At), though at.exe can not access tasks created with schtasks or the Control Panel.

An adversary may use Windows Task Scheduler to execute programs at system startup or on a scheduled basis for persistence. The Windows Task Scheduler can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). Similar to System Binary Proxy Execution, adversaries have also abused the Windows Task Scheduler to potentially mask one-time execution under signed/trusted system processes.(Citation: ProofPoint Serpent)

Adversaries may also create “hidden” scheduled tasks (i.e. Hide Artifacts) that may not be visible to defender tools and manual queries used to enumerate tasks. Specifically, an adversary may hide a task from `schtasks /query` and the Task Scheduler by deleting the associated Security Descriptor (SD) registry value (where deletion of this value must be completed using SYSTEM permissions).(Citation: SigmaHQ)(Citation: Tarrask scheduled task) Adversaries may also employ alternate methods to hide tasks, such as altering the metadata (e.g., `Index` value) within associated registry keys.(Citation: Defending Against Scheduled Task Attacks in Windows Environments)

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.

Several types exist:

### Browser-based Exploitation

Web browsers are a common target through Drive-by Compromise and Spearphishing Link. Endpoint systems may be compromised through normal web browsing or from certain users being targeted by links in spearphishing emails to adversary controlled sites used to exploit the web browser. These often do not require an action by the user for the exploit to be executed.

### Office Applications

Common office and productivity applications such as Microsoft Office are also targeted through Phishing. Malicious files will be transmitted directly as attachments or through links to download them. These require the user to open the document or file for the exploit to run.

### Common Third-party Applications

Other applications that are commonly seen or are part of the software deployed in a target network may also be used for exploitation. Applications such as Adobe Reader and Flash, which are common in enterprise environments, have been routinely targeted by adversaries attempting to gain access to systems. Depending on the software and nature of the vulnerability, some may be exploited in the browser or require the user to open a file. For instance, some Flash exploits have been delivered as objects within Microsoft Office documents.

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.(Citation: Microsoft Service Control Manager) The service control manager is accessible to users via GUI components as well as system utilities such as sc.exe and Net.

PsExec can also be used to execute commands or payloads via a temporary Windows service created through the service control manager API.(Citation: Russinovich Sysinternals) Tools such as PsExec and sc.exe can accept remote servers as arguments and may be used to conduct remote execution.

Adversaries may leverage these mechanisms to execute malicious content. This can be done by either executing a new or modified service. This technique is the execution used in conjunction with Windows Service during service persistence or privilege escalation.

Adversaries may abuse the at utility to perform task scheduling for initial or recurring execution of malicious code. The at utility exists as an executable within Windows, Linux, and macOS for scheduling tasks at a specified time and date. Although deprecated in favor of Scheduled Task’s schtasks in Windows environments, using at requires that the Task Scheduler service be running, and the user to be logged on as a member of the local Administrators group.

On Linux and macOS, at may be invoked by the superuser as well as any users added to the at.allow file. If the at.allow file does not exist, the at.deny file is checked. Every username not listed in at.deny is allowed to invoke at. If the at.deny exists and is empty, global use of at is permitted. If neither file exists (which is often the baseline) only the superuser is allowed to use at.(Citation: Linux at)

Adversaries may use at to execute programs at system startup or on a scheduled basis for Persistence. at can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM).

In Linux environments, adversaries may also abuse at to break out of restricted environments by using a task to spawn an interactive system shell or to run system commands. Similarly, at may also be used for Privilege Escalation if the binary is allowed to run as superuser via sudo.(Citation: GTFObins at)

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 to create a scheduled task.

The deprecated at utility could also be abused by adversaries (ex: At), though at.exe can not access tasks created with schtasks or the Control Panel.

An adversary may use Windows Task Scheduler to execute programs at system startup or on a scheduled basis for persistence. The Windows Task Scheduler can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). Similar to System Binary Proxy Execution, adversaries have also abused the Windows Task Scheduler to potentially mask one-time execution under signed/trusted system processes.(Citation: ProofPoint Serpent)

Adversaries may also create “hidden” scheduled tasks (i.e. Hide Artifacts) that may not be visible to defender tools and manual queries used to enumerate tasks. Specifically, an adversary may hide a task from `schtasks /query` and the Task Scheduler by deleting the associated Security Descriptor (SD) registry value (where deletion of this value must be completed using SYSTEM permissions).(Citation: SigmaHQ)(Citation: Tarrask scheduled task) Adversaries may also employ alternate methods to hide tasks, such as altering the metadata (e.g., `Index` value) within associated registry keys.(Citation: Defending Against Scheduled Task Attacks in Windows Environments)

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).

Adversaries may abuse the at utility to perform task scheduling for initial or recurring execution of malicious code. The at utility exists as an executable within Windows, Linux, and macOS for scheduling tasks at a specified time and date. Although deprecated in favor of Scheduled Task’s schtasks in Windows environments, using at requires that the Task Scheduler service be running, and the user to be logged on as a member of the local Administrators group.

On Linux and macOS, at may be invoked by the superuser as well as any users added to the at.allow file. If the at.allow file does not exist, the at.deny file is checked. Every username not listed in at.deny is allowed to invoke at. If the at.deny exists and is empty, global use of at is permitted. If neither file exists (which is often the baseline) only the superuser is allowed to use at.(Citation: Linux at)

Adversaries may use at to execute programs at system startup or on a scheduled basis for Persistence. at can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM).

In Linux environments, adversaries may also abuse at to break out of restricted environments by using a task to spawn an interactive system shell or to run system commands. Similarly, at may also be used for Privilege Escalation if the binary is allowed to run as superuser via sudo.(Citation: GTFObins at)

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 to create a scheduled task.

The deprecated at utility could also be abused by adversaries (ex: At), though at.exe can not access tasks created with schtasks or the Control Panel.

An adversary may use Windows Task Scheduler to execute programs at system startup or on a scheduled basis for persistence. The Windows Task Scheduler can also be abused to conduct remote Execution as part of Lateral Movement and/or to run a process under the context of a specified account (such as SYSTEM). Similar to System Binary Proxy Execution, adversaries have also abused the Windows Task Scheduler to potentially mask one-time execution under signed/trusted system processes.(Citation: ProofPoint Serpent)

Adversaries may also create “hidden” scheduled tasks (i.e. Hide Artifacts) that may not be visible to defender tools and manual queries used to enumerate tasks. Specifically, an adversary may hide a task from `schtasks /query` and the Task Scheduler by deleting the associated Security Descriptor (SD) registry value (where deletion of this value must be completed using SYSTEM permissions).(Citation: SigmaHQ)(Citation: Tarrask scheduled task) Adversaries may also employ alternate methods to hide tasks, such as altering the metadata (e.g., `Index` value) within associated registry keys.(Citation: Defending Against Scheduled Task Attacks in Windows Environments)

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.

An adversary can use built-in Windows API functions to copy access tokens from existing processes; this is known as token stealing. These token can then be applied to an existing process (i.e. Token Impersonation/Theft) or used to spawn a new process (i.e. Create Process with Token). An adversary must already be in a privileged user context (i.e. administrator) to steal a token. However, adversaries commonly use token stealing to elevate their security context from the administrator level to the SYSTEM level. An adversary can then use a token to authenticate to a remote system as the account for that token if the account has appropriate permissions on the remote system.(Citation: Pentestlab Token Manipulation)

Any standard user can use the runas command, and the Windows API functions, to create impersonation tokens; it does not require access to an administrator account. There are also other mechanisms, such as Active Directory fields, that can be used to modify access tokens.

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).

Adversaries may attempt to manipulate the name of a task or service to make it appear legitimate or benign. Tasks/services executed by the Task Scheduler or systemd will typically be given a name and/or description.(Citation: TechNet Schtasks)(Citation: Systemd Service Units) Windows services will have a service name as well as a display name. Many benign tasks and services exist that have commonly associated names. Adversaries may give tasks or services names that are similar or identical to those of legitimate ones.

Tasks or services contain other fields, such as a description, that adversaries may attempt to make appear legitimate.(Citation: Palo Alto Shamoon Nov 2016)(Citation: Fysbis Dr Web Analysis)

Adversaries may match or approximate the name or location of legitimate files or resources when naming/placing them. This is done for the sake of evading defenses and observation. This may be done by placing an executable in a commonly trusted directory (ex: under System32) or giving it the name of a legitimate, trusted program (ex: svchost.exe). In containerized environments, this may also be done by creating a resource in a namespace that matches the naming convention of a container pod or cluster. Alternatively, a file or container image name given may be a close approximation to legitimate programs/images or something innocuous.

Adversaries may also use the same icon of the file they are trying to mimic.

Adversaries may modify file time attributes to hide new 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. This is done, for example, on files that have been modified or created by the adversary so that they do not appear conspicuous to forensic investigators or file analysis tools.

Timestomping may be used along with file name Masquerading to hide malware and tools.(Citation: WindowsIR Anti-Forensic Techniques)

Adversaries may interact with the Windows Registry to hide configuration information within Registry keys, remove information as part of cleaning up, or as part of other techniques to aid in persistence and execution.

Access to specific areas of the Registry depends on account permissions, some requiring administrator-level access. The built-in Windows command-line utility Reg may be used for local or remote Registry modification. (Citation: Microsoft Reg) Other tools may also be used, such as a remote access tool, which may contain functionality to interact with the Registry through the Windows API.

Registry modifications may also include actions to hide keys, such as prepending key names with a null character, which will cause an error and/or be ignored when read via Reg or other utilities using the Win32 API. (Citation: Microsoft Reghide NOV 2006) Adversaries may abuse these pseudo-hidden keys to conceal payloads/commands used to maintain persistence. (Citation: TrendMicro POWELIKS AUG 2014) (Citation: SpectorOps Hiding Reg Jul 2017)

The Registry of a remote system may be modified to aid in execution of files as part of lateral movement. It requires the remote Registry service to be running on the target system. (Citation: Microsoft Remote) Often Valid Accounts are required, along with access to the remote system’s SMB/Windows Admin Shares for RPC communication.

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.

An adversary can use built-in Windows API functions to copy access tokens from existing processes; this is known as token stealing. These token can then be applied to an existing process (i.e. Token Impersonation/Theft) or used to spawn a new process (i.e. Create Process with Token). An adversary must already be in a privileged user context (i.e. administrator) to steal a token. However, adversaries commonly use token stealing to elevate their security context from the administrator level to the SYSTEM level. An adversary can then use a token to authenticate to a remote system as the account for that token if the account has appropriate permissions on the remote system.(Citation: Pentestlab Token Manipulation)

Any standard user can use the runas command, and the Windows API functions, to create impersonation tokens; it does not require access to an administrator account. There are also other mechanisms, such as Active Directory fields, that can be used to modify access tokens.

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.(Citation: Deloitte Environment Awareness)

Specific checks will vary based on the target and/or adversary, but may involve behaviors such as Windows Management Instrumentation, PowerShell, System Information Discovery, and Query Registry to obtain system information and search for VME artifacts. Adversaries may search for VME artifacts in memory, processes, file system, hardware, and/or the Registry. Adversaries may use scripting to automate these checks into one script and then have the program exit if it determines the system to be a virtual environment.

Checks could include generic system properties such as host/domain name and samples of network traffic. Adversaries may also check the network adapters addresses, CPU core count, and available memory/drive size.

Other common checks may enumerate services running that are unique to these applications, installed programs on the system, manufacturer/product fields for strings relating to virtual machine applications, and VME-specific hardware/processor instructions.(Citation: McAfee Virtual Jan 2017) In applications like VMWare, adversaries can also use a special I/O port to send commands and receive output.

Hardware checks, such as the presence of the fan, temperature, and audio devices, could also be used to gather evidence that can be indicative a virtual environment. Adversaries may also query for specific readings from these devices.(Citation: Unit 42 OilRig Sept 2018)

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.(Citation: SCADAfence_ransomware)

Adversaries may also tamper with artifacts deployed and utilized by security tools. Security tools may make dynamic changes to system components in order to maintain visibility into specific events. For example, security products may load their own modules and/or modify those loaded by processes to facilitate data collection. Similar to Indicator Blocking, adversaries may unhook or otherwise modify these features added by tools (especially those that exist in userland or are otherwise potentially accessible to adversaries) to avoid detection.(Citation: OutFlank System Calls)(Citation: MDSec System Calls)

Adversaries may also focus on specific applications such as Sysmon. For example, the “Start” and “Enable” values in HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlWMIAutologgerEventLog-Microsoft-Windows-Sysmon-Operational may be modified to tamper with and potentially disable Sysmon logging.(Citation: disable_win_evt_logging)

On network devices, adversaries may attempt to skip digital signature verification checks by altering startup configuration files and effectively disabling firmware verification that typically occurs at boot.(Citation: Fortinet Zero-Day and Custom Malware Used by Suspected Chinese Actor in Espionage Operation)(Citation: Analysis of FG-IR-22-369)

In cloud environments, tools disabled by adversaries may include cloud monitoring agents that report back to services such as AWS CloudWatch or Google Cloud Monitor.

Furthermore, although defensive tools may have anti-tampering mechanisms, adversaries may abuse tools such as legitimate rootkit removal kits to impair and/or disable these tools.(Citation: chasing_avaddon_ransomware)(Citation: dharma_ransomware)(Citation: demystifying_ryuk)(Citation: doppelpaymer_crowdstrike) For example, adversaries have used tools such as GMER to find and shut down hidden processes and antivirus software on infected systems.(Citation: demystifying_ryuk)

Additionally, adversaries may exploit legitimate drivers from anti-virus software to gain access to kernel space (i.e. Exploitation for Privilege Escalation), which may lead to bypassing anti-tampering features.(Citation: avoslocker_ransomware)

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).

On Linux and Mac, users can mark specific files as hidden simply by putting a “.” as the first character in the file or folder name (Citation: Sofacy Komplex Trojan) (Citation: Antiquated Mac Malware). Files and folders that start with a period, ‘.’, are by default hidden from being viewed in the Finder application and standard command-line utilities like “ls”. Users must specifically change settings to have these files viewable.

Files on macOS can also be marked with the UF_HIDDEN flag which prevents them from being seen in Finder.app, but still allows them to be seen in Terminal.app (Citation: WireLurker). On Windows, users can mark specific files as hidden by using the attrib.exe binary. Many applications create these hidden files and folders to store information so that it doesn’t clutter up the user’s workspace. For example, SSH utilities create a .ssh folder that’s hidden and contains the user’s known hosts and keys.

Adversaries can use this to their advantage to hide files and folders anywhere on the system and evading a typical user or system analysis that does not incorporate investigation of hidden files.

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.

As well as in-memory techniques, the LSASS process memory can be dumped from the target host and analyzed on a local system.

For example, on the target host use procdump:

* procdump -ma lsass.exe lsass_dump

Locally, mimikatz can be run using:

* sekurlsa::Minidump lsassdump.dmp

* sekurlsa::logonPasswords

Built-in Windows tools such as comsvcs.dll can also be used:

* rundll32.exe C:WindowsSystem32comsvcs.dll MiniDump PID lsass.dmp full(Citation: Volexity Exchange Marauder March 2021)(Citation: Symantec Attacks Against Government Sector)

Windows Security Support Provider (SSP) DLLs are loaded into LSASS process at system start. Once loaded into the LSA, SSP DLLs have access to encrypted and plaintext passwords that are stored in Windows, such as any logged-on user’s Domain password or smart card PINs. The SSP configuration is stored in two Registry keys: HKLMSYSTEMCurrentControlSetControlLsaSecurity Packages and HKLMSYSTEMCurrentControlSetControlLsaOSConfigSecurity Packages. An adversary may modify these Registry keys to add new SSPs, which will be loaded the next time the system boots, or when the AddSecurityPackage Windows API function is called.(Citation: Graeber 2014)

The following SSPs can be used to access credentials:

* Msv: Interactive logons, batch logons, and service logons are done through the MSV authentication package.

* Wdigest: The Digest Authentication protocol is designed for use with Hypertext Transfer Protocol (HTTP) and Simple Authentication Security Layer (SASL) exchanges.(Citation: TechNet Blogs Credential Protection)

* Kerberos: Preferred for mutual client-server domain authentication in Windows 2000 and later.

* CredSSP: Provides SSO and Network Level Authentication for Remote Desktop Services.(Citation: TechNet Blogs Credential Protection)

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

The Registry contains a significant amount of information about the operating system, configuration, software, and security.(Citation: Wikipedia Windows Registry) Information can easily be queried using the Reg utility, though other means to access the Registry exist. Some of the information may help adversaries to further their operation within a network. Adversaries may use the information from Query Registry 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 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:WindowsSystem32Driversetchosts 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)

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.

Tools such as Systeminfo can be used to gather detailed system information. If running with privileged access, a breakdown of system data can be gathered through the systemsetup configuration tool on macOS. As an example, adversaries with user-level access can execute the df -aH command to obtain currently mounted disks and associated freely available space. Adversaries may also leverage a Network Device CLI on network devices to gather detailed system information (e.g. show version).(Citation: US-CERT-TA18-106A) System Information Discovery combined with information gathered from other forms of discovery and reconnaissance can drive payload development and concealment.(Citation: OSX.FairyTale)(Citation: 20 macOS Common Tools and Techniques)

Infrastructure as a Service (IaaS) cloud providers such as AWS, GCP, and Azure allow access to instance and virtual machine information via APIs. Successful authenticated API calls can return data such as the operating system platform and status of a particular instance or the model view of a virtual machine.(Citation: Amazon Describe Instance)(Citation: Google Instances Resource)(Citation: Microsoft Virutal Machine API)

Adversaries may attempt to gather information about attached peripheral devices and components connected to a computer system.(Citation: Peripheral Discovery Linux)(Citation: Peripheral Discovery macOS) 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.

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.(Citation: Deloitte Environment Awareness)

Specific checks will vary based on the target and/or adversary, but may involve behaviors such as Windows Management Instrumentation, PowerShell, System Information Discovery, and Query Registry to obtain system information and search for VME artifacts. Adversaries may search for VME artifacts in memory, processes, file system, hardware, and/or the Registry. Adversaries may use scripting to automate these checks into one script and then have the program exit if it determines the system to be a virtual environment.

Checks could include generic system properties such as host/domain name and samples of network traffic. Adversaries may also check the network adapters addresses, CPU core count, and available memory/drive size.

Other common checks may enumerate services running that are unique to these applications, installed programs on the system, manufacturer/product fields for strings relating to virtual machine applications, and VME-specific hardware/processor instructions.(Citation: McAfee Virtual Jan 2017) In applications like VMWare, adversaries can also use a special I/O port to send commands and receive output.

Hardware checks, such as the presence of the fan, temperature, and audio devices, could also be used to gather evidence that can be indicative a virtual environment. Adversaries may also query for specific readings from these devices.(Citation: Unit 42 OilRig Sept 2018)

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.

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.

Adversaries may abuse various utilities to compress or encrypt data before exfiltration. Some third party utilities may be preinstalled, such as tar on Linux and macOS or zip on Windows systems.

On Windows, diantz or makecab may be used to package collected files into a cabinet (.cab) file. diantz may also be used to download and compress files from remote locations (i.e. Remote Data Staging).(Citation: diantz.exe_lolbas) xcopy on Windows can copy files and directories with a variety of options. Additionally, adversaries may use certutil to Base64 encode collected data before exfiltration.

Adversaries may use also third party utilities, such as 7-Zip, WinRAR, and WinZip, to perform similar activities.(Citation: 7zip Homepage)(Citation: WinRAR Homepage)(Citation: WinZip Homepage)

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.

Protocols such as HTTP/S(Citation: CrowdStrike Putter Panda) and WebSocket(Citation: Brazking-Websockets) that carry web traffic may be very common in environments. HTTP/S packets have many fields and headers in which data can be concealed. An adversary may abuse these protocols to communicate with systems under their control within a victim network while also mimicking normal, expected traffic.

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.(Citation: Talos Olympic Destroyer 2018)(Citation: Novetta Blockbuster)

Adversaries may accomplish this by disabling individual services of high importance to an organization, such as MSExchangeIS, which will make Exchange content inaccessible (Citation: Novetta Blockbuster). In some cases, adversaries may stop or disable many or all services to render systems unusable.(Citation: Talos Olympic Destroyer 2018) Services or processes may not allow for modification of their data stores while running. Adversaries may stop services or processes in order to conduct Data Destruction or Data Encrypted for Impact on the data stores of services like Exchange and SQL Server.(Citation: SecureWorks WannaCry Analysis)