Emond
Adversaries may use Event Monitor Daemon (emond) to establish persistence by scheduling malicious commands to run on predictable event triggers. Emond is a Launch Daemon that accepts events from various services, runs them through a simple rules engine, and takes action. The emond binary at /sbin/emond will load any rules from the /etc/emond.d/rules/ directory and take action once an explicitly defined event takes place.
The rule files are in the plist format and define the name, event type, and action to take. Some examples of event types include system startup and user authentication. Examples of actions are to run a system command or send an email.
The emond service will not launch if there is no file present in the QueueDirectories path /private/var/db/emondClients, specified in the Launch Daemon configuration file at/System/Library/LaunchDaemons/com.apple.emond.plist. Adversaries may abuse this service by writing a rule to execute commands when a defined event occurs, such as system start up or user authentication. Adversaries may also be able to escalate privileges from administrator to root as the emond service is executed with root privileges by the Launch Daemon service.
- Understand the behaviour - read the description and the Atomic Tests to see exactly what the attacker does on a host or network.
- Find the telemetry - what data source would reveal it (process creation, registry, network flow, auth logs). Detection Coverage shows which surfaces already have a rule and which are blind.
- Get or write the detection - adapt ready logic (CAR Analytics, SIEM Detections, Falco, or Sigma via Generate a SIEM detection), or author your own.
- Test it - run an Atomic Test in a lab and confirm your rule actually fires. A detection you have not tested is a hope, not coverage.
- Deploy and tune - push it, then watch for false positives and adjust.