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Description

This analytic will identify suspicious executable or scripts (known file extensions) in list of suspicious file path in Windows. This technique is used by adversaries to evade detection. The suspicious file path are known paths used in the wild and are not common to have executable or scripts.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-05-06
  • Author: Teoderick Contreras, Splunk
  • ID: a7e3f0f0-ae42-11eb-b245-acde48001122

ATT&CK

ID Technique Tactic
T1036 Masquerading Defense Evasion

|tstats `security_content_summariesonly` values(Filesystem.file_path) as file_path count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where (Filesystem.file_name = *.exe OR Filesystem.file_name = *.dll OR Filesystem.file_name = *.sys OR Filesystem.file_name = *.com OR Filesystem.file_name = *.vbs OR Filesystem.file_name = *.vbe OR Filesystem.file_name = *.js OR Filesystem.file_name = *.ps1 OR Filesystem.file_name = *.bat OR Filesystem.file_name = *.cmd OR Filesystem.file_name = *.pif) AND ( Filesystem.file_path = *\\windows\\fonts\\* OR Filesystem.file_path = *\\windows\\temp\\* OR Filesystem.file_path = *\\users\\public\\* OR Filesystem.file_path = *\\windows\\debug\\* OR Filesystem.file_path = *\\Users\\Administrator\\Music\\* OR Filesystem.file_path = *\\Windows\\servicing\\* OR Filesystem.file_path = *\\Users\\Default\\* OR Filesystem.file_path = *Recycle.bin* OR Filesystem.file_path = *\\Windows\\Media\\* OR Filesystem.file_path = *\\Windows\\repair\\* OR Filesystem.file_path = *\\AppData\\Local\\Temp*) by Filesystem.file_create_time Filesystem.process_id  Filesystem.file_name Filesystem.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `executables_or_script_creation_in_suspicious_path_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 Filesystem responsible for the changes from your endpoints into the Endpoint datamodel in the Filesystem node.

Required field

  • _time
  • Filesystem.file_path
  • Filesystem.file_create_time
  • Filesystem.process_id
  • Filesystem.file_name
  • Filesystem.user

Kill Chain Phase

  • Exploitation

Known False Positives

Administrators may allow creation of script or exe in the paths specified. Filter as needed.

RBA

Risk Score Impact Confidence Message
56.0 80 70 Suspicious executable or scripts with file name $file_name$, $file_path$ and process_id $process_id$ executed in suspicious file path in Windows 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

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