T1502Techniquedefense-evasionprivilege-escalationrevokedagent-callable
T1502Parent PID Spoofing
Platforms: Windows
ATT&CK version: 14.1
What it is
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 <code>CreateProcess</code> 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 <code>svchost.exe</code> or <code>consent.exe</code>) 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](https://attack.mitre.org/techniques/T1086)/[Rundll32](https://attack.mitre.org/techniques/T1085) to be <code>explorer.exe</code> rather than an Office document delivered as part of [Spearphishing Attachment](https://attack.mitre.org/techniques/T1193).(Citation: CounterCept PPID Spoofing Dec 2018) This spoofing could be executed via VBA [Scripting](https://attack.mitre.org/techniques/T1064) within a malicious Office document or any code that can perform [Native API](https://attack.mitre.org/techniques/T1106).(Citation: CTD PPID Spoofing Macro Mar 2019)(Citation: CounterCept PPID Spoofing Dec 2018)
Explicitly assigning the PPID may also enable [Privilege Escalation](https://attack.mitre.org/tactics/TA0004) (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 <code>lsass.exe</code>), causing the new process to be elevated via the inherited access token.(Citation: XPNSec PPID Nov 2017)
ATT&CK tactics· 2
References
- https://attack.mitre.org/techniques/T1502
- https://blog.didierstevens.com/2009/11/22/quickpost-selectmyparent-or-playing-with-the-windows-process-tree/
- https://docs.microsoft.com/windows/security/identity-protection/user-account-control/how-user-account-control-works
- https://www.countercept.com/blog/detecting-parent-pid-spoofing/
- https://blog.christophetd.fr/building-an-office-macro-to-spoof-process-parent-and-command-line/
- https://blog.xpnsec.com/becoming-system/
- https://docs.microsoft.com/windows/desktop/ProcThread/process-creation-flags
- https://www.securityinbits.com/malware-analysis/parent-pid-spoofing-stage-2-ataware-ransomware-part-3