Sigma rule: Potential AMSI COM Server Hijacking

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-d3d0c3d681d3, updated 2023-08-17T00:00:00.000Z.

Rule

Title
Potential AMSI COM Server Hijacking
Status
test
Level
high
Author
Nasreddine Bencherchali (Nextron Systems)
Date
2023-01-04
Modified
2023-08-17
File
rules/windows/registry/registry_set/registry_set_amsi_com_hijack.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects changes to the AMSI come server registry key in order disable AMSI scanning functionalities. When AMSI attempts to starts its COM component, it will query its registered CLSID and return a non-existent COM server. This causes a load failure and prevents any scanning methods from being accessed, ultimately rendering AMSI useless

Log source

product
windows
category
registry_set

Detection

selection:
    TargetObject|endswith: '\CLSID\{fdb00e52-a214-4aa1-8fba-4357bb0072ec}\InProcServer32\(Default)'
filter:
    Details: '%windir%\system32\amsi.dll'
condition: selection and not filter

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.defense-impairment
  • attack.t1685

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/registry/registry_set/registry_set_amsi_com_hijack.yml

Sources and licences

  • SigmaHQ

    "Potential AMSI COM Server Hijacking" by Nasreddine Bencherchali (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/registry/registry_set/registry_set_amsi_com_hijack.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Potential AMSI COM Server Hijacking",
entity page, dataset version ref-d3d0c3d681d3, updated 2023-08-17T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/160d2780-31f7-4922-8b3a-efce30e63e96 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 160d2780-31f7-4922-8b3a-efce30e63e96, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.