T1055.003

Thread Execution Hijacking

SUB-TECHNIQUE Stealth Privilege Escalation

Description

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 <code>OpenThread</code>. At this point the process can be suspended then written to, realigned to the injected code, and resumed via <code>SuspendThread </code>, <code>VirtualAllocEx</code>, <code>WriteProcessMemory</code>, <code>SetThreadContext</code>, then <code>ResumeThread</code> respectively.(Citation: Elastic Process Injection July 2017)This is very similar to [Process Hollowing](https://attack.mitre.org/techniques/T1055/012) 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.

Platforms

Windows

Mitigations

M1040 — Behavior Prevention on Endpoint

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Source: MITRE ATT&CK Enterprise matrix. View on attack.mitre.org →