Possible Local System Accounts Enumeration - Linux (via process_creation)

title: Possible Local System Accounts Enumeration - Linux (via process_creation)
id: 8118214c-5f92-5a39-aa16-c72eda79a2da
status: stable
description: This rule detects enumeration of local system accounts. This information can help threat actors determine which local accounts exist on a system to aid in follow-on behavior.
references:
    - https://attack.mitre.org/techniques/T1087/001/
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1087.001/T1087.001.md
    - https://my.f5.com/manage/s/article/K589
    - https://man.freebsd.org/cgi/man.cgi?pwd_mkdb
author: Huntrule Team
date: 2026-01-22
tags:
    - attack.discovery
    - attack.t1087.001
logsource:
    category: process_creation
    product: linux
detection:
    selection_1:
        Image|endswith: '/lastlog'
    selection_2:
        CommandLine|contains: '''x:0:'''
    selection_3:
        Image|endswith:
            - '/cat'
            - '/ed'
            - '/head'
            - '/more'
            - '/nano'
            - '/tail'
            - '/vi'
            - '/vim'
            - '/less'
            - '/emacs'
            - '/sqlite3'
            - '/makemap'
        CommandLine|contains:
            - '/etc/passwd'
            - '/etc/shadow'
            - '/etc/sudoers'
            - '/etc/spwd.db'
            - '/etc/pwd.db'
            - '/etc/master.passwd'
    selection_4:
        Image|endswith: '/id'
    selection_5:
        Image|endswith: '/lsof'
        CommandLine|contains: '-u'
    condition: 1 of selection*
falsepositives:
    - Unknown
level: low