Emond Rules Creation or Modification

Elastic Stack Serverless Security

Identifies the creation or modification of the Event Monitor Daemon (emond) rules. 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.

Rule type: eql

Rule indices:

• auditbeat-*
• logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

• https://www.xorrior.com/emond-persistence/
• https://www.sentinelone.com/blog/how-malware-persists-on-macos/

Tags:

• Elastic
• Host
• macOS
• Threat Detection
• Persistence

Version: 3

Rule authors:

• Elastic

Rule license: Elastic License v2

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define event.ingested and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate event.ingested to @timestamp for this rule to work.

file where event.type != "deletion" and
 file.path : ("/private/etc/emond.d/rules/*.plist", "/etc/emon.d/rules/*.plist", "/private/var/db/emondClients/*")

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Persistence
  • ID: TA0003
  • Reference URL: https://attack.mitre.org/tactics/TA0003/

• Technique:

  • Name: Event Triggered Execution
  • ID: T1546
  • Reference URL: https://attack.mitre.org/techniques/T1546/

• Sub-technique:

  • Name: Emond
  • ID: T1546.014
  • Reference URL: https://attack.mitre.org/techniques/T1546/014/