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Disabling Security Tools

A Sigma rule for process creation on Linux, by Ömer Günal, Alejandro Ortuno, oscd.community.

medium 1 ATT&CK technique 4 programs it names 1 everyday example trips it

What it looks for

its detection, as SigmaHQ writes it
detection:
  selection_carbonblack_1:
    CommandLine|contains|all:
      - 'cbdaemon'
      - 'stop'
    Image|endswith: '/service'
  selection_carbonblack_2:
    CommandLine|contains|all:
      - 'cbdaemon'
      - 'off'
    Image|endswith: '/chkconfig'
  selection_carbonblack_3:
    CommandLine|contains|all:
      - 'cbdaemon'
      - 'stop'
    Image|endswith: '/systemctl'
  selection_carbonblack_4:
    CommandLine|contains|all:
      - 'cbdaemon'
      - 'disable'
    Image|endswith: '/systemctl'
  selection_crowdstrike_1:
    CommandLine|contains|all:
      - 'stop'
      - 'falcon-sensor'
    Image|endswith: '/systemctl'
  selection_crowdstrike_2:
    CommandLine|contains|all:
      - 'disable'
      - 'falcon-sensor'
    Image|endswith: '/systemctl'
  selection_firewall_1:
    CommandLine|contains|all:
      - 'firewalld'
      - 'stop'
    Image|endswith: '/systemctl'
  selection_firewall_2:
    CommandLine|contains|all:
      - 'firewalld'
      - 'disable'
    Image|endswith: '/systemctl'
  selection_iptables_1:
    CommandLine|contains|all:
      - 'iptables'
      - 'stop'
    Image|endswith: '/service'
  selection_iptables_2:
    CommandLine|contains|all:
      - 'ip6tables'
      - 'stop'
    Image|endswith: '/service'
  selection_iptables_3:
    CommandLine|contains|all:
      - 'iptables'
      - 'stop'
    Image|endswith: '/chkconfig'
  selection_iptables_4:
    CommandLine|contains|all:
      - 'ip6tables'
      - 'stop'
    Image|endswith: '/chkconfig'
  selection_selinux:
    CommandLine|contains: '0'
    Image|endswith: '/setenforce'
  condition: 1 of selection*

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 Ömer Günal, Alejandro Ortuno, oscd.community, 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.

Command lines that trip it

everyday examples from tldr-pages, CC BY 4.0, each read by CmdID

Put SELinux in permissive mode on the page for setenforce

setenforce 0Identify

Programs and files it names

their pages here

ATT&CK

the techniques it is tagged with
T1686Disable or Modify System Firewall