Detection rules › Sigma

Uncommon Svchost Parent Process

Severity
medium
Author
Florian Roth (Nextron Systems)
Source
upstream

Detects an uncommon svchost parent process

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1036.005 Masquerading: Match Legitimate Resource Name or Location

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation
Security-Auditing4688A new process has been created.

Stages and Predicates

Stage 1: selection

Image|endswith: '\svchost.exe'

Stage 2: not 1 of filter_main_*

or:
ParentImage|endswith: '\Mrt.exe'
ParentImage|endswith: '\MsMpEng.exe'
ParentImage|endswith: '\TiWorker.exe'
ParentImage|endswith: '\ngen.exe'
ParentImage|endswith: '\rpcnet.exe'
ParentImage|endswith: '\services.exe'
ParentImage: ''
ParentImage: -
ParentImage: null

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
Imageends_with
  • \svchost.exe corpus 20 (sigma 20)
ParentImageends_with
  • \Mrt.exe
  • \MsMpEng.exe corpus 3 (sigma 3)
  • \TiWorker.exe
  • \ngen.exe corpus 2 (sigma 2)
  • \rpcnet.exe corpus 2 (sigma 2)
  • \services.exe corpus 7 (sigma 7)
ParentImageeq
  • - corpus 5 (sigma 5)

Neighbors

Stricter alternatives (narrower than this rule)

The rules below may be useful if you find the current rule is too noisy / lacks specificity.