CmdID / Rules / Windows

Suspicious Child Process Created as System

A Sigma rule for process creation on Windows, by Teymur Kheirkhabarov, Roberto Rodriguez (@Cyb3rWard0g), Open Threat Research (OTR).

high 1 ATT&CK technique 1 program it names

What it looks for

its detection, as SigmaHQ writes it

detection:
  filter_rundll32:
    CommandLine|contains: 'DavSetCookie'
    Image|endswith: '\rundll32.exe'
  selection:
    IntegrityLevel:
      - 'System'
      - 'S-1-16-16384'
    ParentUser|contains:
      - 'AUTHORI'
      - 'AUTORI'
    ParentUser|endswith:
      - '\NETWORK SERVICE'
      - '\LOCAL SERVICE'
    User|contains:
      - 'AUTHORI'
      - 'AUTORI'
    User|endswith:
      - '\SYSTEM'
      - '\Système'
      - '\СИСТЕМА'
  condition: selection and not 1 of filter_*

The rule’s detection, its selections and fields in order of name. The whole rule, with its references and false positives, is on SigmaHQ, by Teymur Kheirkhabarov, Roberto Rodriguez (@Cyb3rWard0g), Open Threat Research (OTR), under the Detection Rule License 1.1. CmdID evaluates it on a command line alone: a test on what a command line cannot show, such as the parent process or the user, is not met.

None of the everyday examples and documented commands on CmdID’s program pages trips it. To see whether a command line does, paste it into CmdID.

Programs and files it names

their pages here

rundll32.exe

ATT&CK

the techniques it is tagged with

T1134.002Access Token Manipulation: Create Process with Token

Suspicious Child Process Created as System

What it looks for

Programs and files it names

ATT&CK

Other rules for T1134.002 Access Token Manipulation: Create Process with Token