Detection rules › Sigma

Suspicious Userinit Child Process

Severity
medium
Author
Florian Roth (Nextron Systems), Samir Bousseaden (idea)
Source
upstream

Detects a suspicious child process of userinit

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1055 Process Injection
Defense EvasionT1055 Process Injection

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation

Stages and Predicates

Stage 1: selection

ParentImage|endswith: '\userinit.exe'

Stage 2: not 1 of filter_main_*

or:
CommandLine: 'C:\Windows\Explorer.EXE'
CommandLine|contains: '\netlogon\'
Image|endswith: '\explorer.exe'
Image: null
OriginalFileName: explorer.exe

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
CommandLineeq
  • C:\Windows\Explorer.EXE
CommandLinematch
  • \netlogon\
Imageends_with
  • \explorer.exe corpus 12 (sigma 12)
OriginalFileNameeq
  • explorer.exe
ParentImageends_with
  • \userinit.exe corpus 3 (sigma 3)