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Description

The following analytic identifies a Microsoft Office product spawning the Windows msdt.exe process. MSDT is a Diagnostics Troubleshooting Wizard native to Windows. This behavior is related to a recently identified sample utilizing protocol handlers to evade preventative controls, including if macros are disabled in the document. During triage, review file modifications for html. In addition, parallel processes including PowerShell and CertUtil.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-05-30
  • Author: Michael Haag, Teoderick Contreras, Splunk
  • ID: 127eba64-c981-40bf-8589-1830638864a7

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1566 Phishing Initial Access
T1566.001 Spearphishing Attachment Initial Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE
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.parent_process_name IN ("winword.exe","excel.exe","powerpnt.exe","outlook.exe","mspub.exe","visio.exe") Processes.process_name=msdt.exe by Processes.dest Processes.user Processes.parent_process 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)` 
| `windows_office_product_spawning_msdt_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_office_product_spawning_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
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.original_file_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_path
  • Processes.process_path
  • Processes.parent_process_id

How To Implement

how 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 should be limited, however filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
100.0 100 100 Office parent process $parent_process_name$ has spawned a child process $process_name$ on host $dest$.

: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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