Detect Emond in Splunk
Adversaries may gain persistence and elevate privileges by executing malicious content triggered by the Event Monitor Daemon (emond). Emond is a Launch Daemon on macOS that accepts events from various services, runs them through a simple rule engine, and takes action. The emond rules files are stored at /etc/emond.d/rules/ and rules are defined in plist format. Adversaries can write malicious event rules to these files to execute arbitrary code when a matching event occurs. Emond runs as root — any process or command triggered by an emond rule executes with root privileges, making this both a persistence and privilege escalation technique.
MITRE ATT&CK
- Tactic
- Privilege Escalation Persistence
- Technique
- T1546 Event Triggered Execution
- Sub-technique
- T1546.014 Emond
- Canonical reference
- https://attack.mitre.org/techniques/T1546/014/
SPL Detection Query
index=syslog sourcetype=syslog host=*mac*
| eval IsEmondFile=if(
match(source, "/etc/emond\.d/(rules/|startupitems/)") OR match(_raw, "emond"),
1, 0
)
| eval IsFileWrite=if(
match(_raw, "(wrote|write|created|WRITE|CREATE|open.*O_CREAT|open.*O_RDWR)"),
1, 0
)
| eval IsPlist=if(match(_raw, "\.plist"), 1, 0)
| where IsEmondFile=1 OR (IsFileWrite=1 AND IsPlist=1 AND match(_raw, "emond"))
| table _time, host, user, _raw, IsEmondFile, IsFileWrite
| sort - _timeDetects emond rule file modifications on macOS using syslog data. Requires macOS Unified Logging forwarded to Splunk or an endpoint agent (such as osquery or a macOS EDR) that captures file system events. Monitors /etc/emond.d/rules/ for new plist file creation. The combination of an emond directory path with a file write event for a .plist file is the primary detection signal.
Data Sources
Required Sourcetypes
False Positives & Tuning
- macOS system updates modifying emond rule files
- Enterprise macOS management tools deploying emond rules
- Security monitoring products using emond
- IT operations creating legitimate emond rules
Other platforms for T1546.014
Testing Methodology
Validate this detection against 3 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 Emond Rule for Startup Persistence
Expected signal: File creation event for /etc/emond.d/rules/argus_test.plist. Process creation for tee writing to the rules directory. On next startup or emond reload, emond spawns the touch command as root — file creation event for /tmp/emond_executed.
- Test 2Verify Emond Service Status
Expected signal: Process creation for launchctl and ls. Read-only — no modifications. Output shows emond service state and all existing rule files.
- Test 3Create Emond Authentication Event Rule
Expected signal: File creation event for /etc/emond.d/rules/argus_auth_test.plist. The authentication event trigger fires on user login, causing emond to spawn the touch command as root.
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