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Description

The following analytic identifies renamed instances of PsExec.exe being utilized on an endpoint. Most instances, it is highly probable to capture Psexec.exe or other SysInternal utility usage with the command-line argument of -accepteula. During triage, validate this is the legitimate version of PsExec by reviewing the PE metadata. In addition, review parallel processes for further suspicious behavior.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-09-16
  • Author: Michael Haag, Splunk
  • ID: 683e6196-b8e8-11eb-9a79-acde48001122

ATT&CK

ID Technique Tactic
T1569 System Services Execution
T1569.002 Service Execution Execution

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_psexec` by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.original_file_name 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `detect_renamed_psexec_filter`

Associated Analytic Story

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.

Required field

  • _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

Kill Chain Phase

  • Exploitation
  • Lateral Movement
  • Execution

Known False Positives

Limited false positives should be present. It is possible some third party applications may use older versions of PsExec, filter as needed.

RBA

Risk Score Impact Confidence Message
27.0 30 90 The following $process_name$ has been identified as renamed, spawning from $parent_process_name$ on $dest$ by $user$.

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: 3