Detect Launchd in Splunk
Adversaries may abuse the launchd daemon to perform task scheduling for initial or recurring execution of malicious code on macOS. The launchd daemon is responsible for loading and maintaining services within the operating system. It processes property list (plist) files found in /System/Library/LaunchDaemons, /Library/LaunchDaemons (system-wide daemons run as root), /Library/LaunchAgents (user agents run for all users), and ~/Library/LaunchAgents (user agents run for the specific user). Adversaries may install malicious plist files in these directories to achieve persistence, privilege escalation (via LaunchDaemons running as root), or execution at system startup or login. This technique is noted as deprecated by MITRE due to inaccurate original characterization, but the underlying abuse of launchd-controlled directories remains a valid and observed persistence mechanism on macOS.
MITRE ATT&CK
- Canonical reference
- https://attack.mitre.org/techniques/T1053/004/
SPL Detection Query
index=mac_logs (sourcetype="macos:unified_log" OR sourcetype="syslog" OR sourcetype="macos:security")
("LaunchDaemons" OR "LaunchAgents" OR "launchctl")
| eval is_plist_creation=if(match(_raw, "(LaunchDaemons|LaunchAgents).+\.plist") AND match(_raw, "(created|modified|written|open for write)"), 1, 0)
| eval is_launchctl_load=if(match(_raw, "launchctl.+(load|bootstrap|submit|start)"), 1, 0)
| eval suspicious_parent=if(match(_raw, "(bash|sh|zsh|python|python3|ruby|perl|curl|wget|osascript|node)"), 1, 0)
| eval suspicious_path=if(match(_raw, "(/tmp/|/var/tmp/|\.hidden|/Users/Shared/)"), 1, 0)
| eval is_daemon_path=if(match(_raw, "Library/LaunchDaemons"), 1, 0)
| eval is_system_path=if(match(_raw, "System/Library"), 1, 0)
| eval alert_score=is_plist_creation + is_launchctl_load + suspicious_parent + suspicious_path
| where alert_score > 0
| eval alert_type=case(
is_plist_creation=1 AND suspicious_parent=1, "SuspiciousPlistCreationByShellOrInterpreter",
is_plist_creation=1 AND suspicious_path=1, "PlistCreatedInSuspiciousPath",
is_launchctl_load=1 AND suspicious_parent=1, "SuspiciousLaunchctlLoadByShell",
is_launchctl_load=1 AND suspicious_path=1, "LaunchctlLoadFromSuspiciousPath",
is_plist_creation=1, "PlistCreatedInLaunchDirectory",
is_launchctl_load=1, "LaunchctlLoadDetected",
true(), "OtherLaunchdActivity"
)
| table _time, host, user, sourcetype, alert_type, alert_score, is_daemon_path, is_system_path, _raw
| sort - alert_score, - _timeDetects launchd abuse on macOS by searching macOS unified logs and syslog for plist file creation or modification in LaunchDaemon/LaunchAgent directories and suspicious launchctl load/bootstrap commands. Assigns a composite alert score based on multiple suspicious indicators including initiating process type, destination path, and command action. Designed for environments forwarding macOS system logs to Splunk.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Legitimate software installation (Homebrew, macOS app installers, enterprise MDM) creating plist files in LaunchDaemons or LaunchAgents directories
- IT management tools (Jamf Pro, Puppet, Chef, Ansible) deploying configuration via launchctl load as part of policy enforcement
- Developer tools and package managers (e.g., Homebrew services) that register background services using plist files
- macOS system updates modifying plist files in /System/Library paths
- Monitoring agents (CrowdStrike, Carbon Black, SentinelOne endpoint sensors) installing their own LaunchDaemon plist files
Other platforms for T1053.004
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Create Malicious LaunchAgent Plist for User Persistence
Expected signal: File creation event for ~/Library/LaunchAgents/com.argus.test.persistence.plist and /tmp/argus_test_payload.sh. Process creation event for launchctl with arguments 'load ~/Library/LaunchAgents/com.argus.test.persistence.plist'. macOS Unified Log entry for launchd registering the new service with label 'com.argus.test.persistence'. Subsequent execution of /bin/bash with /tmp/argus_test_payload.sh as argument, initiated by launchd.
- Test 2Create Root LaunchDaemon Plist for System-Level Persistence
Expected signal: File creation event for /Library/LaunchDaemons/com.argus.test.daemon.plist with initiating process sudo/bash running as root. Process creation events for sudo and launchctl with 'load /Library/LaunchDaemons/com.argus.test.daemon.plist'. macOS Unified Log entry from launchd registering system daemon. The IsDaemon flag in the KQL query should be set to true.
- Test 3Launchctl Load from Suspicious Temp Directory Path
Expected signal: File creation event for /tmp/com.argus.tmppersist.plist. Process creation event for launchctl with command line containing 'load /tmp/com.argus.tmppersist.plist' — the /tmp path is a key indicator. macOS Unified Log entries for launchd service registration from a temp path.
- Test 4Simulate Adversary Plist Drop via curl and Shell
Expected signal: Process creation for bash with the dropper script as command. File creation event for ~/Library/LaunchAgents/com.argus.dropper.test.plist with InitiatingProcessFileName=bash — the suspicious parent detection fires. Process creation for launchctl initiated by bash. macOS Unified Log shows the full execution chain: bash → file write → launchctl → launchd registration.
References (10)
- https://attack.mitre.org/techniques/T1053/004/
- https://developer.apple.com/library/content/documentation/MacOSX/Conceptual/BPSystemStartup/Chapters/CreatingLaunchdJobs.html
- https://www.virusbulletin.com/uploads/pdf/conference/vb2014/VB2014-Wardle.pdf
- https://objective-see.org/blog.html
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1053.004/T1053.004.md
- https://www.sentinelone.com/blog/how-malware-persists-on-macos/
- https://www.crowdstrike.com/blog/how-to-detect-and-prevent-mac-malware/
- https://managingosx.wordpress.com/2015/10/15/launchd-is-not-a-valid-way-to-run-a-job-at-a-scheduled-time/
- https://support.apple.com/guide/terminal/apdc6c1077b-5d5d-4d35-9c19-60f2397b2369/mac
- https://github.com/SigmaHQ/sigma/tree/master/rules/macos
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