Detect Emond in CrowdStrike LogScale
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/
LogScale Detection Query
#event_simpleName=/(EndOfProcess|ProcessRollup2|SyntheticProcessRollup2|FileWritten|FileCreated)/
| event_platform=Mac
| (
FilePath = /\/etc\/emond\.d\/(rules\/|startupitems\/)/ OR
FilePath = /\/etc\/emond\.d\// OR
(FileName = /\.plist$/ AND (FilePath = /emond/ OR CommandLine = /emond/))
)
| rename(field="ComputerName", as="hostname")
| rename(field="UserName", as="username")
| rename(field="FileName", as="file_name")
| rename(field="FilePath", as="file_path")
| rename(field="CommandLine", as="initiating_cmd")
| table([timestamp, hostname, username, file_name, file_path, initiating_cmd, #event_simpleName])
| sort(timestamp, order=desc)Detects macOS file write and creation events targeting the emond rules directory (/etc/emond.d/rules/) or emond-associated plist files using CrowdStrike Falcon telemetry. Surfaces FileWritten and FileCreated events on Mac endpoints with file paths matching emond configuration locations, enabling detection of persistence mechanisms that abuse the Event Monitor Daemon to execute arbitrary commands as root.
Data Sources
Required Tables
False Positives & Tuning
- Jamf Pro or other MDM solutions writing emond rule plist files to enrolled macOS devices during configuration profile application or policy enforcement
- CrowdStrike Falcon's own file monitoring activity generating internal events that may match emond path patterns during telemetry collection
- macOS system administrators deploying authorized emond-based monitoring rules as part of a legitimate IT operations or compliance automation workflow
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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