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

T1121: Regsvcs/Regasm

Regsvcs and Regasm are Windows command-line utilities that are used to register .NET Component Object Model (COM) assemblies. Both are digitally signed by Microsoft. [1] [2]

Adversaries can use Regsvcs and Regasm to proxy execution of code through a trusted Windows utility. Both utilities may be used to bypass process whitelisting through use of attributes within the binary to specify code that should be run before registration or unregistration: [ComRegisterFunction] or [ComUnregisterFunction] respectively. The code with the registration and unregistration attributes will be executed even if the process is run under insufficient privileges and fails to execute. [3][4]

EnterpriseT1121TechniqueObject v1.3 Modified
Discuss defensive coverage Back to ATT&CK
Historical object

This ATT&CK object is revoked or deprecated in the current MITRE ATT&CK release.

It remains available for historical context and inbound links. Use current ATT&CK relationships and replacement guidance before basing detection or reporting work on this page.

Glexia's Take

Analyst summary pending validation

Glexia publishes ATT&CK takes only after source-hash and schema validation. Until then, use the official MITRE definition below and the defensive relationship context on this page.

Official MITRE ATT&CK definition

Regsvcs/Regasm

Regsvcs and Regasm are Windows command-line utilities that are used to register .NET Component Object Model (COM) assemblies. Both are digitally signed by Microsoft. [1] [2]

Adversaries can use Regsvcs and Regasm to proxy execution of code through a trusted Windows utility. Both utilities may be used to bypass process whitelisting through use of attributes within the binary to specify code that should be run before registration or unregistration: [ComRegisterFunction] or [ComUnregisterFunction] respectively. The code with the registration and unregistration attributes will be executed even if the process is run under insufficient privileges and fails to execute. [3][4]

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.

1 rows
Domain ID Name Relationship / procedure
Enterprise T1218.009 Regsvcs/Regasm Sub-technique This object revoked by Regsvcs/Regasm.
Relationship explorer

All related ATT&CK context

revoked by · Technique T1218.009: Regsvcs/Regasm Enterprise
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
1.3
Created
Modified
Raw hash
b271f479f0e673f2...
Imported snapshots across ATT&CK releases (1)
Release Bundle imported Object version Modified Status Raw hash
19.1 1.3 Current bundle Revoked b271f479f0e6…
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]
    MSDN Regsvcs

    Microsoft. (n.d.). Regsvcs.exe (.NET Services Installation Tool). Retrieved July 1, 2016.

    Open source URL
  2. [2]
    MSDN Regasm

    Microsoft. (n.d.). Regasm.exe (Assembly Registration Tool). Retrieved July 1, 2016.

    Open source URL
  3. [3]
    LOLBAS Regsvcs

    LOLBAS. (n.d.). Regsvcs.exe. Retrieved July 31, 2019.

    Open source URL
  4. [4]
    LOLBAS Regasm

    LOLBAS. (n.d.). Regasm.exe. Retrieved July 31, 2019.

    Open source URL
  5. [5]
    mitre-attack T1121
    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