Unusual Child Processes of RunDLL32

Elastic Stack Serverless Security

Identifies child processes of unusual instances of RunDLL32 where the command line parameters were suspicious. Misuse of RunDLL32 could indicate malicious activity.

Rule type: eql

Rule indices:

• logs-endpoint.events.*
• winlogbeat-*
• logs-windows.*

Severity: high

Risk score: 73

Runs every: 30m

Searches indices from: now-60m (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: None

Tags:

• Elastic
• Host
• Windows
• Threat Detection
• Defense Evasion

Version: 100

Rule authors:

• Elastic

Rule license: Elastic License v2

sequence with maxspan=1h
  [process where event.type in ("start", "process_started") and
     (process.name : "rundll32.exe" or process.pe.original_file_name == "RUNDLL32.EXE") and
      process.args_count == 1
  ] by process.entity_id
  [process where event.type in ("start", "process_started") and process.parent.name : "rundll32.exe"
  ] by process.parent.entity_id

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Defense Evasion
  • ID: TA0005
  • Reference URL: https://attack.mitre.org/tactics/TA0005/

• Technique:

  • Name: System Binary Proxy Execution
  • ID: T1218
  • Reference URL: https://attack.mitre.org/techniques/T1218/

• Sub-technique:

  • Name: Rundll32
  • ID: T1218.011
  • Reference URL: https://attack.mitre.org/techniques/T1218/011/