Class: Trojan
A malicious program designed to electronically spy on the user’s activities (intercept keyboard input, take screenshots, capture a list of active applications, etc.). The collected information is sent to the cybercriminal by various means, including email, FTP, and HTTP (by sending data in a request).Read more
Platform: Win32
Win32 is an API on Windows NT-based operating systems (Windows XP, Windows 7, etc.) that supports execution of 32-bit applications. One of the most widespread programming platforms in the world.Family: Pasta
No family descriptionExamples
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Tactics and Techniques: Mitre*
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 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 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.
Modifying or disabling a system firewall may enable adversary C2 communications, lateral movement, and/or data exfiltration that would otherwise not be allowed. For example, adversaries may add a new firewall rule for a well-known protocol (such as RDP) using a non-traditional and potentially less securitized port (i.e. Non-Standard Port).(Citation: change_rdp_port_conti)
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 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)
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)
Adversaries may communicate using a protocol and port pairing that are typically not associated. For example, HTTPS over port 8088(Citation: Symantec Elfin Mar 2019) or port 587(Citation: Fortinet Agent Tesla April 2018) 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.
Adversaries may also make changes to victim systems to abuse non-standard ports. For example, Registry keys and other configuration settings can be used to modify protocol and port pairings.(Citation: change_rdp_port_conti)
Adversaries may communicate using a protocol and port pairing that are typically not associated. For example, HTTPS over port 8088(Citation: Symantec Elfin Mar 2019) or port 587(Citation: Fortinet Agent Tesla April 2018) 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.
Adversaries may also make changes to victim systems to abuse non-standard ports. For example, Registry keys and other configuration settings can be used to modify protocol and port pairings.(Citation: change_rdp_port_conti)
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