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Elastic Docs ›Elastic Security Solution [8.2] ›Detections and alerts ›Prebuilt rule reference

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: 5 minutes

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

Maximum alerts per execution: 100

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution

Version: 5 (version history)

Added (Elastic Stack release): 7.11.0

Last modified (Elastic Stack release): 8.2.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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Microsoft Windows installers leveraging RunDLL32 for installation.

Investigation guide

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## Config

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")

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 5 (8.2.0 release)
  • Formatting only
Version 4 (7.13.0 release)

  • Updated query, changed from:

    process where event.type in ("start", "process_started") and
process.name : ("cmd.exe", "powershell.exe") and process.parent.name
: "rundll32.exe" and /* common FPs can be added here */ not
process.parent.args :
"C:\\Windows\\System32\\SHELL32.dll,RunAsNewUser_RunDLL"
Version 3 (7.12.0 release)
  • Formatting only
Version 2 (7.11.2 release)
  • Formatting only
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