Linux process commands stopping firewall and security services

Flags Linux commands that stop/disable firewall/security services or set SELinux enforcement to 0.

FreeReviewedSigma · Medium · v2

Product: linux
Category: process_creation
Author: Ömer Günal, Alejandro Ortuno, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-06-17
Updated: 2026-07-31

ATT&CK techniques

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies Linux process activity where commands attempt to stop or disable common security controls, including iptables/ip6tables, firewalld, and endpoint protection services (e.g., cbdaemon and falcon-sensor). Such actions can impair host defenses and are consistent with attacker attempts to evade detection or maintain persistence. It relies on process creation telemetry, matching image paths and command-line arguments like stop/disable/off and service identifiers.

Reporting behind it

Related detections9 linkedT1686 — drag to rearrange

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Suspicious Outbound Firewall Block Rule Added via Netsh Advfirewall

Malicious Windows Firewall Disable via Netsh

OpenSSH Server Firewall Configuration on Windows - Firewall (via firewall-as)

Suspicious Firewall Rule Added Using PowerShell or CMD (via firewall-as)

Suspicious Firewall Rule Masquerading as CloudExperienceHost via netsh

Suspicious Firewall Rule Masquerading As Windows Update (via process_creation)

Linux process commands stopping firewall and security services

Pivot detection · T1686 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

linux-service-commands-stopping-or-disabling-security-tools-iptables-firewalld-c-e3a8a052

title: Linux process commands stopping firewall and security services
id: 6c166716-026e-4be7-9515-5643f4d79a03
status: test
description: This rule identifies Linux process activity where commands attempt to stop or disable common security controls, including iptables/ip6tables, firewalld, and endpoint protection services (e.g., cbdaemon and falcon-sensor). Such actions can impair host defenses and are consistent with attacker attempts to evade detection or maintain persistence. It relies on process creation telemetry, matching image paths and command-line arguments like stop/disable/off and service identifiers.
references:
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1562.004/T1562.004.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/linux/process_creation/proc_creation_lnx_security_tools_disabling.yml
author: Ömer Günal, Alejandro Ortuno, oscd.community, Huntrule Team
date: 2020-06-17
modified: 2022-10-09
tags:
  - attack.defense-impairment
  - attack.t1686
logsource:
  category: process_creation
  product: linux
detection:
  selection_iptables_1:
    Image|endswith: /service
    CommandLine|contains|all:
      - iptables
      - stop
  selection_iptables_2:
    Image|endswith: /service
    CommandLine|contains|all:
      - ip6tables
      - stop
  selection_iptables_3:
    Image|endswith: /chkconfig
    CommandLine|contains|all:
      - iptables
      - stop
  selection_iptables_4:
    Image|endswith: /chkconfig
    CommandLine|contains|all:
      - ip6tables
      - stop
  selection_firewall_1:
    Image|endswith: /systemctl
    CommandLine|contains|all:
      - firewalld
      - stop
  selection_firewall_2:
    Image|endswith: /systemctl
    CommandLine|contains|all:
      - firewalld
      - disable
  selection_carbonblack_1:
    Image|endswith: /service
    CommandLine|contains|all:
      - cbdaemon
      - stop
  selection_carbonblack_2:
    Image|endswith: /chkconfig
    CommandLine|contains|all:
      - cbdaemon
      - off
  selection_carbonblack_3:
    Image|endswith: /systemctl
    CommandLine|contains|all:
      - cbdaemon
      - stop
  selection_carbonblack_4:
    Image|endswith: /systemctl
    CommandLine|contains|all:
      - cbdaemon
      - disable
  selection_selinux:
    Image|endswith: /setenforce
    CommandLine|contains: "0"
  selection_crowdstrike_1:
    Image|endswith: /systemctl
    CommandLine|contains|all:
      - stop
      - falcon-sensor
  selection_crowdstrike_2:
    Image|endswith: /systemctl
    CommandLine|contains|all:
      - disable
      - falcon-sensor
  condition: 1 of selection*
falsepositives:
  - Legitimate administration activities
level: medium
license: DRL-1.1
related:
  - id: e3a8a052-111f-4606-9aee-f28ebeb76776
    type: derived

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