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Description

The search looks for a file named “test.txt” written to the windows system directory tree, which is consistent with Samsam propagation.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
  • Last Updated: 2018-12-14
  • Author: Rico Valdez, Splunk
  • ID: 493a879d-519d-428f-8f57-a06a0fdc107e

Annotations

ATT&CK
ID Technique Tactic
T1486 Data Encrypted for Impact Impact
Kill Chain Phase
  • Delivery
NIST
  • PR.PT
  • DE.CM
CIS20
  • CIS 8
CVE 
1
2
3
4
5
6

| 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_name) as file_name from datamodel=Endpoint.Filesystem where Filesystem.file_path=*\\windows\\system32\\test.txt by Filesystem.file_path 
| `drop_dm_object_name(Filesystem)` 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
| `samsam_test_file_write_filter`

Macros

The SPL above uses the following Macros:

Note that samsam_test_file_write_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

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

How To Implement

You must be ingesting data that records the 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.

Known False Positives

No false positives have been identified.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
12.0 60 20 A samsam ransomware test file creation in $file_path$ in host $dest$

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

source | version: 1