Detection rules › Sigma

Winrs Local Command Execution

Severity
high
Author
Liran Ravich, Nasreddine Bencherchali
Source
upstream

Detects the execution of Winrs.exe where it is used to execute commands locally. Commands executed this way are launched under Winrshost.exe and can represent proxy execution used for defense evasion or lateral movement.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1218 System Binary Proxy Execution
Lateral MovementT1021.006 Remote Services: Windows Remote Management

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation

Stages and Predicates

Stage 1: all of selection_img

or:
Image|endswith: '\winrs.exe'
OriginalFileName: winrs.exe

Stage 2: all of selection_local_ip

or:
CommandLine|contains: '/r:127.0.0.1'
CommandLine|contains: '/r:[::1]'
CommandLine|contains: '/r:localhost'
CommandLine|contains: '/remote:127.0.0.1'
CommandLine|contains: '/remote:[::1]'
CommandLine|contains: '/remote:localhost'

Stage 3: selection_img

or:
Image|endswith: '\winrs.exe'
OriginalFileName: winrs.exe

Stage 4: not 1 of filter_main_remote

or:
CommandLine|contains: '/r:'
CommandLine|contains: '/remote:'

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
CommandLinematch
  • /r:
  • /r:127.0.0.1
  • /r:[::1]
  • /r:localhost
  • /remote:
  • /remote:127.0.0.1
  • /remote:[::1]
  • /remote:localhost
Imageends_with
  • \winrs.exe
OriginalFileNameeq
  • winrs.exe