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MITRE ATT&CK sub-technique

T1055.004 — Asynchronous Procedure Call

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T1055.004 (Asynchronous Procedure Call) is a MITRE ATT&CK sub-technique tracked in WhisperGraph, serving the Stealth, Privilege Escalation tactics.

Description

Adversaries may inject malicious code into processes via the asynchronous procedure call (APC) queue in order to evade process-based defenses as well as possibly elevate privileges. APC injection is a method of executing arbitrary code in the address space of a separate live process. APC injection is commonly performed by attaching malicious code to the APC Queue (Citation: Microsoft APC) of a process's thread. Queued APC functions are executed when the thread enters an alterable state.(Citation: Microsoft APC) A handle to an existing victim process is first created with native Windows API calls such as <code>OpenThread</code>. At this point <code>QueueUserAPC</code> can be used to invoke a function (such as <code>LoadLibrayA</code> pointing to a malicious DLL). A variation of APC injection, dubbed "Early Bird injection", involves creating a suspended process in which malicious code can be written and executed before the process' entry point (and potentially subsequent anti-malware hooks) via an APC. (Citation: CyberBit Early Bird Apr 2018) AtomBombing (Citation: ENSIL AtomBombing Oct 2016) is another variation that utilizes APCs to invoke malicious code previously written to the global atom table.(Citation: Microsoft Atom Table) 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 APC injection may also evade detection from security products since the execution is masked under a legitimate process.

Tactics

Related techniques

Parent technique: T1055 · Process Injection

Threat actors observed using this technique

© The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation.

Related pages

Pivot from T1055.004 into its tactic, related techniques and the actors that use it.

Queries

Resolves the segment to this technique or tactic.


MATCH (t:ATTACK_PATTERN {name: $id})
RETURN t.id AS id, t.name AS name, t.kind AS kind, t.description AS description
Run yourself →

The tactic(s) this technique serves.


MATCH (t:ATTACK_PATTERN {name: $id})-[:USES_TACTIC]->(tac:ATTACK_PATTERN)
RETURN tac.id AS id, tac.name AS name
LIMIT 10
Run yourself →

This id's parent technique, if it is a sub-technique.


MATCH (p:ATTACK_PATTERN {name: $parentId})
RETURN p.id AS id, p.name AS name
LIMIT 1
Run yourself →

Sub-techniques of this technique, if any.


MATCH (c:ATTACK_PATTERN) WHERE c.id STARTS WITH $subPrefix
RETURN c.id AS id, c.name AS name
ORDER BY c.id
LIMIT 25
Run yourself →

Threat actors observed using this technique.


MATCH (a:ACTOR)-[:USES_TECHNIQUE]->(t:ATTACK_PATTERN {name: $id})
RETURN a.name AS name
LIMIT 100
Run yourself →

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