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Description

The following analytic identifies instances of the WinDBG process spawning AutoIt3. This behavior may indicate malicious activity as AutoIt3 is often used by threat actors for scripting malicious automation. The search specifically looks for instances where the parent process name is 'windbg.exe' and the process name is 'autoit3.exe' or 'autoit*.exe'. During the triage process, it is recommended to review the file path for additional artifacts that may provide further insights into the event.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2023-10-31
  • Author: Michael Haag, Splunk
  • ID: 7aec015b-cd69-46c3-85ed-dac152056aa4

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1059 Command and Scripting Interpreter Execution
Kill Chain Phase
  • Installation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes  where Processes.parent_process_name=windbg.exe  AND (Processes.process_name IN ("autoit3.exe", "autoit*.exe") OR Processes.original_file_name IN ("autoit3.exe", "autoit*.exe")) by Processes.dest, Processes.user, Processes.parent_process_name, Processes.process_name, Processes.original_file_name, Processes.process, Processes.process_id, Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| eval matches_extension=if(match(process, "\\.(au3
|a3x
|exe
|aut
|aup)$"), "Yes", "No") 
| search matches_extension="Yes" 
| `windows_windbg_spawning_autoit3_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_windbg_spawning_autoit3_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.process_name
  • Processes.original_file_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_id

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

False positives will only be present if the WinDBG process legitimately spawns AutoIt3. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
100.0 100 100 An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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