Local System Accounts Discovery - Linux

 1title: Local System Accounts Discovery - Linux
 2id: b45e3d6f-42c6-47d8-a478-df6bd6cf534c
 3status: test
 4description: Detects enumeration of local systeam accounts. This information can help adversaries determine which local accounts exist on a system to aid in follow-on behavior.
 5references:
 6    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1087.001/T1087.001.md
 7author: Alejandro Ortuno, oscd.community
 8date: 2020/10/08
 9modified: 2022/11/27
10tags:
11    - attack.discovery
12    - attack.t1087.001
13logsource:
14    category: process_creation
15    product: linux
16detection:
17    selection_1:
18        Image|endswith: '/lastlog'
19    selection_2:
20        CommandLine|contains: '''x:0:'''
21    selection_3:
22        Image|endswith:
23            - '/cat'
24            - '/head'
25            - '/tail'
26            - '/more'
27        CommandLine|contains:
28            - '/etc/passwd'
29            - '/etc/shadow'
30            - '/etc/sudoers'
31    selection_4:
32        Image|endswith: '/id'
33    selection_5:
34        Image|endswith: '/lsof'
35        CommandLine|contains: '-u'
36    condition: 1 of selection*
37falsepositives:
38    - Legitimate administration activities
39level: low