Local System Accounts Discovery Attempt - Linux

detection:
  filter_optional_landscape_sysinfo:
    Image|endswith: '/who'
    ParentCommandLine|contains: '/usr/bin/landscape-sysinfo'
  selection_getent:
    CommandLine|contains:
      - ' passwd'
      - ' shadow'
    Image|endswith: '/getent'
  selection_id:
    Image|endswith: '/id'
  selection_lastlog:
    Image|endswith:
      - '/lastlog'
      - '/last'
      - '/lastb'
  selection_lsof:
    CommandLine|contains: '-u'
    Image|endswith: '/lsof'
  selection_read_utilities:
    CommandLine|contains:
      - '/etc/passwd'
      - '/etc/shadow'
      - '/etc/sudoers'
      - 'master.passwd'
      - 'pwd.db'
    Image|endswith:
      - '/cat'
      - '/ed'
      - '/emacs'
      - '/head'
      - '/less'
      - '/makemap'
      - '/more'
      - '/nano'
      - '/sqlite3'
      - '/tail'
      - '/vi'
      - '/vim'
  selection_root_string:
    CommandLine|contains: 'x:0:'
  selection_who:
    Image|endswith:
      - '/finger'
      - '/users'
      - '/w'
      - '/who'
  selection_ypcat:
    CommandLine|contains: 'passwd'
    Image|endswith: '/ypcat'
  condition: 1 of selection_* and not 1 of filter_optional_*

The rule’s detection, its selections and fields in order of name. The whole rule, with its references and false positives, is on SigmaHQ, by Alejandro Ortuno, oscd.community, CheraghiMilad, under the Detection Rule License 1.1. CmdID evaluates it on a command line alone: a test on what a command line cannot show, such as the parent process or the user, is not met.

And 21 more examples on CmdID’s program pages.

The commands documented for chown, finger, getent, last, lastb, setfacl, sg trip it too: each is on its program’s page, read by CmdID.