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The following analytic detects the creation of a file named "test.txt" within the Windows system directory, indicative of Samsam ransomware propagation. It leverages file-system activity data from the Endpoint data model, specifically monitoring file paths within the Windows System32 directory. This activity is significant as it aligns with known Samsam ransomware behavior, which uses such files for propagation and execution. If confirmed malicious, this could lead to ransomware deployment, resulting in data encryption, system disruption, and potential data loss. Immediate investigation and remediation are crucial to prevent further damage.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-14
  • Author: Rico Valdez, Splunk
  • ID: 493a879d-519d-428f-8f57-a06a0fdc107e




ID Technique Tactic
T1486 Data Encrypted for Impact Impact
Kill Chain Phase
  • Actions On Objectives
  • DE.CM
  • CIS 10
| 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`


The SPL above uses the following Macros:

:information_source: 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 fields

List of fields required to use this analytic.

  • _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


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

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.


Test Dataset

Replay any dataset to Splunk Enterprise by using our tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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