Class: Exploit
Exploits are programs that contain data or executable code which take advantage of one or more vulnerabilities in software running on a local or remote computer for clearly malicious purposes. Often, malicious users employ an exploit to penetrate a victim computer in order to subsequently install malicious code (for example, to infect all visitors to a compromised website with a malicious program). Additionally, exploits are commonly used by Net-Worms in order to hack a victim computer without any action being required from the user. Nuker programs are notable among exploits; such programs send specially crafted requests to local or remote computers, causing the system to crash.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: Exploit.Win32.ShellCode
No family descriptionExamples
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DFB4BB8C6C348809DFAC4D69B1713D0A
Tactics and Techniques: Mitre*
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, and .cpl.
Adversaries may employ various forms of Masquerading and Obfuscated Files or Information to increase the likelihood that a user will open and successfully execute a malicious file. These methods may include using a familiar naming convention and/or password protecting the file and supplying instructions to a user on how to open it.(Citation: Password Protected Word Docs)
While Malicious File frequently occurs shortly after Initial Access it may occur at other phases of an intrusion, such as when an adversary places a file in a shared directory or on a user’s desktop hoping that a user will click on it. This activity may also be seen shortly after Internal Spearphishing.
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, and .cpl.
Adversaries may employ various forms of Masquerading and Obfuscated Files or Information to increase the likelihood that a user will open and successfully execute a malicious file. These methods may include using a familiar naming convention and/or password protecting the file and supplying instructions to a user on how to open it.(Citation: Password Protected Word Docs)
While Malicious File frequently occurs shortly after Initial Access it may occur at other phases of an intrusion, such as when an adversary places a file in a shared directory or on a user’s desktop hoping that a user will click on it. This activity may also be seen shortly after Internal Spearphishing.
Adversaries may spoof the parent process identifier (PPID) of a new process to evade process-monitoring defenses or to elevate privileges. New processes are typically spawned directly from their parent, or calling, process unless explicitly specified. One way of explicitly assigning the PPID of a new process is via the CreateProcess API call, which supports a parameter that defines the PPID to use.(Citation: DidierStevens SelectMyParent Nov 2009) This functionality is used by Windows features such as User Account Control (UAC) to correctly set the PPID after a requested elevated process is spawned by SYSTEM (typically via svchost.exe or consent.exe) rather than the current user context.(Citation: Microsoft UAC Nov 2018)
Adversaries may abuse these mechanisms to evade defenses, such as those blocking processes spawning directly from Office documents, and analysis targeting unusual/potentially malicious parent-child process relationships, such as spoofing the PPID of PowerShell/Rundll32 to be explorer.exe rather than an Office document delivered as part of Spearphishing Attachment.(Citation: CounterCept PPID Spoofing Dec 2018) This spoofing could be executed via Visual Basic within a malicious Office document or any code that can perform Native API.(Citation: CTD PPID Spoofing Macro Mar 2019)(Citation: CounterCept PPID Spoofing Dec 2018)
Explicitly assigning the PPID may also enable elevated privileges given appropriate access rights to the parent process. For example, an adversary in a privileged user context (i.e. administrator) may spawn a new process and assign the parent as a process running as SYSTEM (such as lsass.exe), causing the new process to be elevated via the inherited access token.(Citation: XPNSec PPID Nov 2017)
Adversaries may spoof the parent process identifier (PPID) of a new process to evade process-monitoring defenses or to elevate privileges. New processes are typically spawned directly from their parent, or calling, process unless explicitly specified. One way of explicitly assigning the PPID of a new process is via the CreateProcess API call, which supports a parameter that defines the PPID to use.(Citation: DidierStevens SelectMyParent Nov 2009) This functionality is used by Windows features such as User Account Control (UAC) to correctly set the PPID after a requested elevated process is spawned by SYSTEM (typically via svchost.exe or consent.exe) rather than the current user context.(Citation: Microsoft UAC Nov 2018)
Adversaries may abuse these mechanisms to evade defenses, such as those blocking processes spawning directly from Office documents, and analysis targeting unusual/potentially malicious parent-child process relationships, such as spoofing the PPID of PowerShell/Rundll32 to be explorer.exe rather than an Office document delivered as part of Spearphishing Attachment.(Citation: CounterCept PPID Spoofing Dec 2018) This spoofing could be executed via Visual Basic within a malicious Office document or any code that can perform Native API.(Citation: CTD PPID Spoofing Macro Mar 2019)(Citation: CounterCept PPID Spoofing Dec 2018)
Explicitly assigning the PPID may also enable elevated privileges given appropriate access rights to the parent process. For example, an adversary in a privileged user context (i.e. administrator) may spawn a new process and assign the parent as a process running as SYSTEM (such as lsass.exe), causing the new process to be elevated via the inherited access token.(Citation: XPNSec PPID Nov 2017)
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 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 spoof the parent process identifier (PPID) of a new process to evade process-monitoring defenses or to elevate privileges. New processes are typically spawned directly from their parent, or calling, process unless explicitly specified. One way of explicitly assigning the PPID of a new process is via the CreateProcess API call, which supports a parameter that defines the PPID to use.(Citation: DidierStevens SelectMyParent Nov 2009) This functionality is used by Windows features such as User Account Control (UAC) to correctly set the PPID after a requested elevated process is spawned by SYSTEM (typically via svchost.exe or consent.exe) rather than the current user context.(Citation: Microsoft UAC Nov 2018)
Adversaries may abuse these mechanisms to evade defenses, such as those blocking processes spawning directly from Office documents, and analysis targeting unusual/potentially malicious parent-child process relationships, such as spoofing the PPID of PowerShell/Rundll32 to be explorer.exe rather than an Office document delivered as part of Spearphishing Attachment.(Citation: CounterCept PPID Spoofing Dec 2018) This spoofing could be executed via Visual Basic within a malicious Office document or any code that can perform Native API.(Citation: CTD PPID Spoofing Macro Mar 2019)(Citation: CounterCept PPID Spoofing Dec 2018)
Explicitly assigning the PPID may also enable elevated privileges given appropriate access rights to the parent process. For example, an adversary in a privileged user context (i.e. administrator) may spawn a new process and assign the parent as a process running as SYSTEM (such as lsass.exe), causing the new process to be elevated via the inherited access token.(Citation: XPNSec PPID Nov 2017)
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.
One such example is the use of certutil to decode a remote access tool portable executable file that has been hidden inside a certificate file.(Citation: Malwarebytes Targeted Attack against Saudi Arabia) Another example is using the Windows copy /b command to reassemble binary fragments into a malicious payload.(Citation: Carbon Black Obfuscation Sept 2016)
Sometimes a user’s action may be required to open it for deobfuscation or decryption as part of User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. (Citation: Volexity PowerDuke November 2016)
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 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)
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)
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 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.
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.
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