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.*

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:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution

Version: 8

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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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 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule query

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process where 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