Try in Splunk Security Cloud

Description

The search looks for file writes with extensions consistent with a SamSam ransomware attack.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2018-12-14
  • Author: Rico Valdez, Splunk
  • ID: 02c6cfc2-ae66-4735-bfc7-6291da834cbf

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime values(Filesystem.user) as user values(Filesystem.dest) as dest values(Filesystem.file_path) as file_path from datamodel=Endpoint.Filesystem by Filesystem.file_name 
| `drop_dm_object_name(Filesystem)` 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)`
| rex field=file_name "(?<file_extension>\.[^\.]+)$" 
| search file_extension=.stubbin OR file_extension=.berkshire OR file_extension=.satoshi OR file_extension=.sophos OR file_extension=.keyxml 
| `file_with_samsam_extension_filter`

Associated Analytic Story

How To Implement

You must be ingesting data that records file-system activity from your hosts to populate the Endpoint file-system data-model node. If you are using Sysmon, you will need a Splunk Universal Forwarder on each endpoint from which you want to collect data.

Required field

  • _time
  • Filesystem.user
  • Filesystem.dest
  • Filesystem.file_path
  • Filesystem.file_name

Kill Chain Phase

  • Installation

Known False Positives

Because these extensions are not typically used in normal operations, you should investigate all results.

RBA

Risk Score Impact Confidence Message
90.0 100 90 File writes $file_name$ with extensions consistent with a SamSam ransomware attack seen 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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