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 Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-05-30
- Author: Michael Haag, Teoderick Contreras, Splunk
- ID: e1d5145f-38fe-42b9-a5d5-457796715f97
|T1218||System Binary Proxy Execution||Defense Evasion|
Kill Chain Phase
- CIS 3
- CIS 5
- CIS 16
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=msdt.exe Processes.process IN ("*ms-msdt:/id*","*ms-msdt:-id*","*/id*") AND (Processes.process="*IT_BrowseForFile=*" OR Processes.process="*IT_RebrowseForFile=*" OR Processes.process="*.xml*") AND Processes.process="*PCWDiagnostic*" by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_execute_arbitrary_commands_with_msdt_filter`
The SPL above uses the following Macros:
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.
How To Implement
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the
Endpoint datamodel in the
Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
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
|100.0||100||100||A parent process $parent_process_name$ has spawned a child process $process_name$ on host $dest$ possibly indicative of indirect command execution.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 2