Rundll32 Control RunDLL Hunt

Name:Rundll32 Control RunDLL Hunt
id:c8e7ced0-10c5-11ec-8b03-acde48001122
version:7
date:2025-02-10
author:Michael Haag, Splunk
status:production
type:Hunting
Description:The following analytic identifies instances of rundll32.exe executing with `Control_RunDLL` in the command line, which is indicative of loading a .cpl or other file types. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs and command-line arguments. This activity is significant as rundll32.exe can be exploited to execute malicious Control Panel Item files, potentially linked to CVE-2021-40444. If confirmed malicious, this could allow attackers to execute arbitrary code, escalate privileges, or maintain persistence within the environment.
Data_source:

• -Sysmon EventID 1
• -Windows Event Log Security 4688
• -CrowdStrike ProcessRollup2

search:| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_rundll32` Processes.process=*Control_RunDLL* by Processes.action Processes.dest Processes.original_file_name Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path Processes.user Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `rundll32_control_rundll_hunt_filter`

how_to_implement:The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives:This is a hunting detection, meant to provide a understanding of how voluminous control_rundll is within the environment.
References:
  -https://strontic.github.io/xcyclopedia/library/rundll32.exe-111474C61232202B5B588D2B512CBB25.html
  -https://app.any.run/tasks/36c14029-9df8-439c-bba0-45f2643b0c70/
  -https://attack.mitre.org/techniques/T1218/011/
  -https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40444
  -https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.002/T1218.002.yaml
  -https://redcanary.com/blog/intelligence-insights-december-2021/
drilldown_searches:
  :
tags:
  analytic_story:
    - 'Suspicious Rundll32 Activity'
    - 'Microsoft MSHTML Remote Code Execution CVE-2021-40444'
    - 'Living Off The Land'
  asset_type:Endpoint
  cve:
    - 'CVE-2021-40444'
  mitre_attack_id:
    - 'T1218.011'
  product:
    - 'Splunk Enterprise'
    - 'Splunk Enterprise Security'
    - 'Splunk Cloud'
  security_domain:endpoint

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.002/atomic_red_team/windows-sysmon.log
  source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
  sourcetype: XmlWinEventLog
manual_test:None