macOS Service Disruption Activity

Status: experimental
Severity: medium
Log source: product macos, service endpointsecurity
Author: Eric Brown - Nebulock, Inc.
Source: github.com/Nebulock-Inc/macos-coresigma

Detects execution of service control tools (launchctl, killall, pkill) with parameters targeting system services or multiple processes. May indicate service disruption for impact or denial of service attacks.

Known false positives

System administration and service management
Software updates requiring service restarts
Legitimate process termination
Troubleshooting and maintenance activities
Root user administrative actions

MITRE ATT&CK coverage

Tactic	Techniques
Impact	`T1489` Service Stop `T1529` System Shutdown/Reboot

Rule body

title: macOS Service Disruption Activity
id: e673e584-70d1-4b1e-9bdf-48f7eb0064d9
status: experimental
description: 'Detects execution of service control tools (launchctl, killall, pkill)
  with

  parameters targeting system services or multiple processes. May indicate service

  disruption for impact or denial of service attacks.

  '
author: Eric Brown - Nebulock, Inc.
date: 2025/10/31
modified: 2025/10/31
references:
- https://attack.mitre.org/techniques/T1489/
- https://attack.mitre.org/techniques/T1529/
logsource:
  product: macos
  service: endpointsecurity
detection:
  selection_event:
    esf.event_type: 9
    event.action: exec
  selection_launchctl:
    Image|endswith: /launchctl
    CommandLine|contains:
    - unload
    - remove
    - disable
    - stop
  selection_kill:
    Image|endswith:
    - killall
    - pkill
    CommandLine|contains:
    - '-9'
    - SIGKILL
    - -KILL
  selection_root:
    UserId: 0
  condition: selection_event and (selection_launchctl or selection_kill) and not selection_root
falsepositives:
- System administration and service management
- Software updates requiring service restarts
- Legitimate process termination
- Troubleshooting and maintenance activities
- Root user administrative actions
fields:
- Image
- CommandLine
- ProcessId
- ParentProcessId
- User
tags:
- attack.impact
- attack.t1489
- attack.t1529
level: medium

Stages and Predicates

Stage 0: `condition`

selection_event and (selection_launchctl or selection_kill) and not selection_root

Stage 1: `selection_event`

selection_event:
  esf.event_type: 9
  event.action: exec

Stage 2: `selection_launchctl`

selection_launchctl:
  Image|endswith: /launchctl
  CommandLine|contains:
  - unload
  - remove
  - disable
  - stop

Stage 3: `selection_kill`

selection_kill:
  Image|endswith:
  - killall
  - pkill
  CommandLine|contains:
  - '-9'
  - SIGKILL
  - -KILL

Stage 4: `not selection_root`

selection_root:
  UserId: 0

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`UserId`	eq	`0`	`excludes:UserId` `field:"UserId" value:"0"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`-9` `-KILL` `SIGKILL` `disable` `remove` `stop` `unload`	`field:"CommandLine" kind:match`
`Image`	ends_with	`/launchctl` `killall` `pkill`	`field:"Image" kind:ends_with`
`esf.event_type`	eq	`9`	`field:"esf.event_type" kind:eq value:"9"`
`event.action`	eq	`exec`	`field:"EventType" kind:eq value:"exec"`