Sigma rule: Local System Accounts Discovery - Linux

Rule

Title

Local System Accounts Discovery - Linux

Status

test

Level

low

Author

Alejandro Ortuno, oscd.community, CheraghiMilad

Date

2020-10-08

Modified

2024-12-10

File

rules/linux/process_creation/proc_creation_lnx_local_account.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects enumeration of local system accounts. This information can help adversaries determine which local accounts exist on a system to aid in follow-on behavior.

Log source

product

linux

category

process_creation

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*

False positives (as the rule lists them)

• Legitimate administration activities

Tags

• attack.discovery
• attack.t1087.001

MITRE ATT&CK ids this rule names

• T1087.001

References

• 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

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/linux/process_creation/proc_creation_lnx_local_account.yml