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
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
Put SELinux in permissive mode on the page for setenforce
setenforce 0IdentifyPrograms and files it names
ATT&CK
T1686Disable or Modify System Firewall