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Description

The following analytic identifies a recently disclosed arbitraty command execution using Windows msdt.exe - a Diagnostics Troubleshooting Wizard. The sample identified will use the ms-msdt:/ protocol handler to load msdt.exe to retrieve a remote payload. During triage, review file modifications for html. Identify parallel process execution that may be related, including an Office Product.

  • Type: TTP
  • Product: Splunk Behavioral Analytics
  • Datamodel: Endpoint_Processes
  • Last Updated: 2022-09-15
  • Author: Michael Haag, Splunk
  • ID: f253f9c2-10f0-4cc8-b469-f505ba8c2038

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1218 System Binary Proxy Execution Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • PR.PT
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
ID Summary CVSS
CVE-2022-30190 Microsoft Windows Support Diagnostic Tool (MSDT) Remote Code Execution Vulnerability. 9.3
1
2
3
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5
6
| from read_ssa_enriched_events() 
| eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"), "string", null)), process_name=lower(ucast(map_get(input_event, "process_name"), "string", null)), process_path=ucast(map_get(input_event, "process_path"), "string", null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string", null), event_id=ucast(map_get(input_event, "event_id"), "string", null) 
| where cmd_line IS NOT NULL AND process_name IS NOT NULL AND process_name="msdt.exe" AND (like (cmd_line, "%msdt%") OR like (cmd_line, "%ms-msdt:%") OR like (cmd_line, "%ms-msdt:/id%") OR like (cmd_line, "%ms-msdt:-id%") OR like (cmd_line, "%ms-msdt:/id%")) AND (like (cmd_line, "%it_browseforfile=%") OR like (cmd_line, "%it_rebrowseforfile=%") OR like (cmd_line, "%.xml%")) AND like (cmd_line, "%pcwdiagnostic%") 
| eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"), "string", null)), body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name", process_name, "parent_process_name", parent_process_name, "process_path", process_path]) 
| into write_ssa_detected_events();

Macros

The SPL above uses the following Macros:

:information_source: windows_execute_arbitrary_commands_with_msdt_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.

  • _time
  • dest_device_id
  • process_name
  • parent_process_name
  • process_path
  • dest_user_id
  • process
  • cmd_line

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

False positives may be present, filter as needed. Added .xml to potentially capture any answer file usage. Remove as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
100.0 100 100 $process_name$ on $dest_device_id$ under user $dest_user_id$ possibly indicative of indirect command execution.

: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

source | version: 1