Command Shell Activity Started via RunDLL32

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Command Shell Activity Started via RunDLL32

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Identifies command shell activity started via RunDLL32, which is commonly abused by attackers to host malicious code.

Rule type: eql

Rule indices:

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

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Execution
  • Tactic: Credential Access
  • Tactic: Defense Evasion
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend
  • Data Source: Sysmon

Version: 109

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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Setup

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 version 8.2. Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate event.ingested to @timestamp. For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html

Rule query

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process where host.os.type == "windows" and event.type == "start" and
 process.name : ("cmd.exe", "powershell.exe") and
  process.parent.name : "rundll32.exe" and process.parent.command_line != null and
  /* common FPs can be added here */
  not process.parent.args : ("C:\\Windows\\System32\\SHELL32.dll,RunAsNewUser_RunDLL",
                             "C:\\WINDOWS\\*.tmp,zzzzInvokeManagedCustomActionOutOfProc")

Framework: MITRE ATT&CKTM