Live Active security incident? Get immediate response
MITRE ATT&CK® Technique

T1055.011: Extra Window Memory Injection

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.

Before creating a window, graphical Windows-based processes must prescribe to or register a windows class, which stipulate appearance and behavior (via windows procedures, which are functions that handle input/output of data).[1] Registration of new windows classes can include a request for up to 40 bytes of EWM to be appended to the allocated memory of each instance of that class. This EWM is intended to store data specific to that window and has specific application programming interface (API) functions to set and get its value. [2] [3]

Although small, the EWM is large enough to store a 32-bit pointer and is often used to point to a windows procedure. Malware may possibly utilize this memory location in part of an attack chain that includes writing code to shared sections of the process’s memory, placing a pointer to the code in EWM, then invoking execution by returning execution control to the address in the process’s EWM.

Execution granted through EWM injection may allow access to both the target process's memory and possibly elevated privileges. Writing payloads to shared sections also avoids the use of highly monitored API calls such as WriteProcessMemory and CreateRemoteThread.[4] More sophisticated malware samples may also potentially bypass protection mechanisms such as data execution prevention (DEP) by triggering a combination of windows procedures and other system functions that will rewrite the malicious payload inside an executable portion of the target process. [5] [6]

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 EWM injection may also evade detection from security products since the execution is masked under a legitimate process.

EnterpriseT1055.011Sub-techniqueObject v2.0 Modified
Discuss defensive coverage Back to ATT&CK
Glexia's Take

Analyst context for executives and security teams

Analyst confidence Medium

Extra Window Memory Injection is a Windows process-injection sub-technique that can let malicious code run inside another graphical process, potentially hiding behind a legitimate process and inheriting its access. For leaders, the practical issue is not the small Windows memory structure itself; it is whether endpoint defenses and SOC workflows can recognize abnormal process behavior when common high-signal APIs such as WriteProcessMemory or CreateRemoteThread may not be used.

Executive priority

Prioritize this as part of Windows endpoint resilience and privilege-escalation readiness. It matters for business continuity because injected code may operate under trusted processes, complicating containment, evidence collection, and confidence in host-based alerts. Security leaders should ask whether endpoint behavior-prevention controls are deployed and monitored, whether process-injection detections include less common Windows GUI mechanisms, and whether incident responders can investigate suspicious execution inside otherwise legitimate processes.

Technical view

ATT&CK lists this as a Windows sub-technique of Process Injection under stealth and privilege-escalation. The behavior involves abuse of Extra Window Memory associated with registered window classes and window procedures, potentially storing a pointer that redirects execution to code in the target process. Since MITRE does not provide official detection text for this object, SOC and detection engineering teams should validate coverage against the related ATT&CK detection strategy DET0217 and against the broader T1055 process-injection analytic set. Focus validation on anomalous GUI/window-class behavior, unexpected use of GetWindowLong/SetWindowLong-style APIs, suspicious memory permissions or shared-section activity, and execution context that does not match the legitimate process’s normal behavior.

Likely telemetry

  • Windows endpoint process and thread activity
  • Endpoint detection and response behavioral events
  • API or function-call telemetry related to window classes, window procedures, GetWindowLong, and SetWindowLong where available
  • Memory and module telemetry showing suspicious executable regions, shared sections, or unexpected code execution in another process
  • Process lineage, command-line, image path, signer, and integrity-level context

Detection direction

  • Confirm whether existing process-injection detections cover EWM-specific behavior, not only WriteProcessMemory and CreateRemoteThread patterns.
  • Use the related DET0217 detection strategy as the primary ATT&CK-linked detection reference, while testing locally because official detection text is not supplied for this technique object.
  • Tune detections around abnormal GUI process behavior and unexpected window procedure or EWM manipulation, with allowlisting for legitimate applications that use window classes normally.
  • Correlate memory anomalies with process lineage, privilege level, signer reputation, and network or file activity to reduce false positives.
  • Include ATT&CK relationship context in hunting: Epic and Power Loader are listed as software using this technique, but do not treat that as evidence of current activity without local telemetry.

Mitigation priorities

  • Apply the related M1040 mitigation: behavior prevention on endpoint, emphasizing real-time analysis of suspicious process behavior, files, API calls, and endpoint events.
  • Prioritize endpoint controls that can detect or block anomalous process injection patterns rather than relying only on static signatures.
  • Harden monitoring for privileged and high-value Windows workstations and servers where injected execution would create greater operational or identity risk.
  • Ensure incident response playbooks include collection of process memory, process lineage, loaded modules, and security-alert context for suspected injection cases.
  • Use validation exercises to prove that prevention and alerting still work when common process-injection APIs are not the only detection trigger.
Analyst notes and limits

This object is narrowly scoped to Windows and is a sub-technique of T1055 Process Injection. ATT&CK relationships show mitigation by M1040, detection by DET0217, revocation of older T1181 into this object, and use by Epic and Power Loader. Those relationships provide useful prioritization and hunting context but should not be interpreted as current exploitation or attribution.

MITRE provides no official detection text in the supplied object, so detection guidance must be validated against DET0217, broader process-injection coverage, and local endpoint telemetry. The supplied fields do not support claims about active exploitation, affected customer environments, specific vendor coverage, or guaranteed prevention.

Official MITRE ATT&CK definition

Extra Window Memory Injection

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.

Before creating a window, graphical Windows-based processes must prescribe to or register a windows class, which stipulate appearance and behavior (via windows procedures, which are functions that handle input/output of data).[1] Registration of new windows classes can include a request for up to 40 bytes of EWM to be appended to the allocated memory of each instance of that class. This EWM is intended to store data specific to that window and has specific application programming interface (API) functions to set and get its value. [2] [3]

Although small, the EWM is large enough to store a 32-bit pointer and is often used to point to a windows procedure. Malware may possibly utilize this memory location in part of an attack chain that includes writing code to shared sections of the process’s memory, placing a pointer to the code in EWM, then invoking execution by returning execution control to the address in the process’s EWM.

Execution granted through EWM injection may allow access to both the target process's memory and possibly elevated privileges. Writing payloads to shared sections also avoids the use of highly monitored API calls such as WriteProcessMemory and CreateRemoteThread.[4] More sophisticated malware samples may also potentially bypass protection mechanisms such as data execution prevention (DEP) by triggering a combination of windows procedures and other system functions that will rewrite the malicious payload inside an executable portion of the target process. [5] [6]

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 EWM injection may also evade detection from security products since the execution is masked under a legitimate process.

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

ATT&CK relationship table

Related techniques

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

2 rows
Domain ID Name Relationship / procedure
Enterprise T1055 Process Injection This object subtechnique of Process Injection.
Enterprise T1181 Extra Window Memory Injection Extra Window Memory Injection revoked by this object.
Associated objects

Groups, software, and campaigns

Relationship explorer

All related ATT&CK context

subtechnique of · Technique T1055: Process Injection Enterprise detects · Detection Strategy DET0217: Detection Strategy for Extra Window Memory (EWM) Injection on Windows Enterprise uses · Malware S0091: Epic Enterprise revoked by · Technique T1181: Extra Window Memory Injection Enterprise mitigates · Mitigation M1040: Behavior Prevention on Endpoint Enterprise uses · Malware S0177: Power Loader Enterprise
Mitigations

Mitigation direction

Mitigation Enterprise

M1040: Behavior Prevention on Endpoint

Behavior Prevention on Endpoint refers to the use of technologies and strategies to detect and block potentially malicious activities by analyzing the behavior of processes, files, API calls, and other endpoint events. Rather than relying solely on known signatures, this approach leverages heuristics, machine learning, and real-time monitoring to identify anomalous patterns indicative of an attack. This mitigation can be implemented through the following measures:

Suspicious Process Behavior:

- Implementation: Use Endpoint Detection and Response (EDR) tools to monitor and block processes exhibiting unusual behavior, such as privilege escalation attempts. - Use Case: An attacker uses a known vulnerability to spawn a privileged process from a user-level application. The endpoint tool detects the abnormal parent-child process relationship and blocks the action.

Unauthorized File Access:

- Implementation: Leverage Data Loss Prevention (DLP) or endpoint tools to block processes attempting to access sensitive files without proper authorization. - Use Case: A process tries to read or modify a sensitive file located in a restricted directory, such as /etc/shadow on Linux or the SAM registry hive on Windows. The endpoint tool identifies this anomalous behavior and prevents it.

Abnormal API Calls:

- Implementation: Implement runtime analysis tools to monitor API calls and block those associated with malicious activities. - Use Case: A process dynamically injects itself into another process to hijack its execution. The endpoint detects the abnormal use of APIs like `OpenProcess` and `WriteProcessMemory` and terminates the offending process.

Exploit Prevention:

- Implementation: Use behavioral exploit prevention tools to detect and block exploits attempting to gain unauthorized access. - Use Case: A buffer overflow exploit is launched against a vulnerable application. The endpoint detects the anomalous memory write operation and halts the process.

Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates .

ATT&CK release
19.1
Object version
2.0
Created
Modified
Raw hash
36e8d848cfefd60c...
Imported snapshots across ATT&CK releases (1)
Release Bundle imported Object version Modified Status Raw hash
19.1 2.0 Current bundle 36e8d848cfef…
Raw source

Mirrored ATT&CK source object

The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.

Open mirrored raw JSON Open MITRE-hosted copy
Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    Microsoft Window Classes

    Microsoft. (n.d.). About Window Classes. Retrieved December 16, 2017.

    Open source URL
  2. [2]
    Microsoft GetWindowLong function

    Microsoft. (n.d.). GetWindowLong function. Retrieved December 16, 2017.

    Open source URL
  3. [3]
    Microsoft SetWindowLong function

    Microsoft. (n.d.). SetWindowLong function. Retrieved December 16, 2017.

    Open source URL
  4. [4]
    Elastic Process Injection July 2017

    Hosseini, A. (2017, July 18). Ten Process Injection Techniques: A Technical Survey Of Common And Trending Process Injection Techniques. Retrieved December 7, 2017.

    Open source URL
  5. [5]
    MalwareTech Power Loader Aug 2013

    MalwareTech. (2013, August 13). PowerLoader Injection – Something truly amazing. Retrieved December 16, 2017.

    Open source URL
  6. [6]
    WeLiveSecurity Gapz and Redyms Mar 2013

    Matrosov, A. (2013, March 19). Gapz and Redyms droppers based on Power Loader code. Retrieved December 16, 2017.

    Open source URL
  7. [7]
    mitre-attack T1055.011
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.

Official MITRE ATT&CK site Official STIX data repository MITRE ATT&CK terms of use