System Owner or User Discovery - Linux

Status: test
Severity: low
Log source: product linux, service auditd
Author: Timur Zinniatullin, oscd.community
Source: github.com/SigmaHQ/sigma

Detects the execution of host or user discovery utilities such as "whoami", "hostname", "id", etc. Adversaries may use the information from System Owner/User Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

Known false positives

Admin activity

MITRE ATT&CK coverage

Tactic	Techniques
Discovery	`T1033` System Owner/User Discovery

Telemetry coverage

Platform	Record / event type
Linux	auditd EXECVE record: Arguments supplied to the execve system call

Rule body

title: System Owner or User Discovery - Linux
id: 9a0d8ca0-2385-4020-b6c6-cb6153ca56f3
status: test
description: |
    Detects the execution of host or user discovery utilities such as "whoami", "hostname", "id", etc.
    Adversaries may use the information from System Owner/User Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1033/T1033.md
author: Timur Zinniatullin, oscd.community
date: 2019-10-21
modified: 2025-06-04
tags:
    - attack.discovery
    - attack.t1033
logsource:
    product: linux
    service: auditd
detection:
    selection:
        type: 'EXECVE'
        a0:
            - 'hostname'
            - 'id'
            - 'last'
            - 'uname'
            - 'users'
            - 'w'
            - 'who'
            - 'whoami'
    condition: selection
falsepositives:
    - Admin activity
level: low

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    type: 'EXECVE'
    a0:
        - 'hostname'
        - 'id'
        - 'last'
        - 'uname'
        - 'users'
        - 'w'
        - 'who'
        - 'whoami'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`a0`	eq	`hostname` `id` `last` `uname` `users` `w` `who` `whoami`	`field:"a0" kind:eq`
`type`	eq	`EXECVE`	`field:"type" kind:eq value:"EXECVE"`