Linux Local Groups Discovery via /groups or /etc/group File Enumeration

Detects Linux commands and utilities used to enumerate local groups and read /etc/group.

FreeReviewedSigma · Low · v2

Product: linux
Category: process_creation
Author: Ömer Günal, Alejandro Ortuno, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-10-11
Updated: 2026-07-31

ATT&CK techniques

Discovery

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
- T1069.001Local Groups
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies attempts to enumerate local system groups by executing commands that reference /etc/group or by running a process whose image path ends with /groups. Adversaries may use this information to discover permission assignments and guide subsequent privilege and access attempts. The detection relies on process creation telemetry, matching executable image paths ending in specific utility names and command-line strings containing /etc/group.

Reporting behind it

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Linux Local Groups Discovery via /groups or /etc/group File Enumeration

Pivot detection · T1069.001 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

linux-local-system-groups-enumeration-via-groups-cat-to-etc-group-676381a6

title: Linux Local Groups Discovery via /groups or /etc/group File Enumeration
id: 45ec4608-dc99-4fd0-b300-2512e62d47d5
status: test
description: This rule identifies attempts to enumerate local system groups by executing commands that reference /etc/group or by running a process whose image path ends with /groups. Adversaries may use this information to discover permission assignments and guide subsequent privilege and access attempts. The detection relies on process creation telemetry, matching executable image paths ending in specific utility names and command-line strings containing /etc/group.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1069.001/T1069.001.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/linux/process_creation/proc_creation_lnx_local_groups.yml
author: Ömer Günal, Alejandro Ortuno, oscd.community, Huntrule Team
date: 2020-10-11
modified: 2025-06-04
tags:
  - attack.discovery
  - attack.t1069.001
logsource:
  category: process_creation
  product: linux
detection:
  selection_1:
    Image|endswith: /groups
  selection_2:
    Image|endswith:
      - /cat
      - /ed
      - /head
      - /less
      - /more
      - /nano
      - /tail
      - /vi
      - /vim
    CommandLine|contains: /etc/group
  condition: 1 of selection_*
falsepositives:
  - Legitimate administration activities
level: low
license: DRL-1.1
related:
  - id: 676381a6-15ca-4d73-a9c8-6a22e970b90d
    type: derived

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