Unusual Child Processes of RunDLL32

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: 21

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: 4

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: Signed 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/