Detection rules › Sigma

Potential PSFactoryBuffer COM Hijacking

Severity
high
Author
BlackBerry Threat Research and Intelligence Team - @Joseliyo_Jstnk
Source
upstream

Detects changes to the PSFactory COM InProcServer32 registry. This technique was used by RomCom to create persistence storing a malicious DLL.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1546.015 Event Triggered Execution: Component Object Model Hijacking
Privilege EscalationT1546.015 Event Triggered Execution: Component Object Model Hijacking

Event coverage

ProviderEvent IDTitle
Sysmon13RegistryEvent (Value Set)

Stages and Predicates

Stage 1: selection

TargetObject|endswith: '\CLSID\{c90250f3-4d7d-4991-9b69-a5c5bc1c2ae6}\InProcServer32\(Default)'

Stage 2: not filter_main

Details: ['%windir%\System32\ActXPrxy.dll', 'C:\Windows\System32\ActXPrxy.dll']

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Detailseq
  • %windir%\System32\ActXPrxy.dll
  • C:\Windows\System32\ActXPrxy.dll
TargetObjectends_with
  • \CLSID\{c90250f3-4d7d-4991-9b69-a5c5bc1c2ae6}\InProcServer32\(Default)