Group Membership Reconnaissance Via Whoami.EXE

A Sigma rule for process creation on Windows, by Nasreddine Bencherchali (Nextron Systems).

medium 1 ATT&CK technique 2 programs it names 1 everyday example trips it

What it looks for

its detection, as SigmaHQ writes it

detection:
  selection_cli:
    CommandLine|contains:
      - ' /groups'
      - ' -groups'
  selection_img:
    - Image|endswith: '\whoami.exe'
    - OriginalFileName: 'whoami.exe'
  condition: all of selection_*

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 Nasreddine Bencherchali (Nextron Systems), 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.

Command lines that trip it

everyday examples from tldr-pages, CC BY 4.0, each read by CmdID

Display the groups that the current user is a member of on the page for whoami

whoami /groupsIdentify

Programs and files it names

their pages here

whoamiwhoami.exe

ATT&CK

the techniques it is tagged with

T1033System Owner/User Discovery

Group Membership Reconnaissance Via Whoami.EXE

What it looks for

Command lines that trip it

Programs and files it names

ATT&CK

Other rules for T1033 System Owner/User Discovery