T1055.011sub-technique of T1055 Process Injection

Extra Window Memory Injection

Windowsnothing on this site yetT1055.011 on attack.mitre.org

Adversaries may inject malicious code into process via Extra Window Memory (EWM) in order to evade process-based defenses as well as possibly elevate privileges. EWM injection is a method of executing arbitrary code in the address space of a separate live process.
MITRE ATT&CK 19.2, retrieved 2026-09-12

If this is happening now

Checklists and playbooks to open while the alert is still live.

Playbook for this stage

Cloud account compromise

Impossible travel, an unrecognised inbox rule, or a reported invoice-fraud attempt.

how MITRE says to see it

Detection Strategy for Extra Window Memory (EWM) Injection on Windows

Detects adversary manipulation of Extra Window Memory (EWM) in a GUI process, where the attacker uses SetWindowLong or SetClassLong to redirect function pointers to injected shellcode stored in shared memory, then triggers execution via a window message like SendNotifyMessage.

what reduces it

M1040 Behavior Prevention on Endpoint. Some endpoint security solutions can be configured to block some types of process injection based on common sequences of behavior that occur during the injection process.

the rest of T1055

T1055.001 Dynamic-link Library Injection · not covered yet
T1055.002 Portable Executable Injection · not covered yet
T1055.003 Thread Execution Hijacking · not covered yet
T1055.004 Asynchronous Procedure Call · not covered yet
T1055.005 Thread Local Storage · not covered yet
T1055.008 Ptrace System Calls · not covered yet
T1055.009 Proc Memory · not covered yet
T1055.012 Process Hollowing · not covered yet
T1055.013 Process Doppelgänging · not covered yet
T1055.014 VDSO Hijacking · not covered yet
T1055.015 ListPlanting · not covered yet

The description, detection analytics and mitigations are reproduced from MITRE ATT&CK, version 19.2, under its terms of use. The checklists, hunts, labs and everything else linked here are this site’s.