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Description

This analytic will identify suspicious series of process executions. We have observed that post exploit framework tools like Koadic and Meterpreter will launch an excessive number of processes with distinct file paths from Windows\Temp to execute actions on objective. This behavior is extremely anomalous compared to typical application behaviors that use Windows\Temp.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-06-03
  • Author: Michael Hart, Splunk
  • ID: 23587b6a-c479-11eb-b671-acde48001122

ATT&CK

ID Technique Tactic
T1059 Command and Scripting Interpreter Execution

| tstats `security_content_summariesonly` values(Processes.process) as process distinct_count(Processes.process) as distinct_process_count  min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process = "*\\Windows\\Temp\\*" by Processes.dest Processes.user  _time span=20m 
| where distinct_process_count > 37 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `excessive_number_of_distinct_processes_created_in_windows_temp_folder_filter`

Associated Analytic Story

How To Implement

To successfully implement this search, you need to be ingesting logs with the full process path in the process field of CIM's Process data model. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Tune and filter known instances where renamed sc.exe may be used.

Required field

  • _time
  • Processes.process
  • Processes.dest
  • Processes.user

Kill Chain Phase

  • Exploitation

Known False Positives

Many benign applications will create processes from executables in Windows\Temp, although unlikely to exceed the given threshold. Filter as needed.

RBA

Risk Score Impact Confidence Message
80.0 80 100 Multiple processes were executed out of windows\temp within a short amount of time on $dest$.

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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