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Description

The following analytic detects the stopping of the Windows Security Account Manager (SAM) service via command-line, typically using the "net stop samss" command. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line executions. This activity is significant because stopping the SAM service can disrupt authentication mechanisms and is often associated with ransomware attacks like Ryuk. If confirmed malicious, this action could lead to unauthorized access, privilege escalation, and potential system-wide compromise.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-20
  • Author: Rod Soto, Jose Hernandez, Splunk
  • ID: 69c12d59-d951-431e-ab77-ec426b8d65e6

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1489 Service Stop Impact
Kill Chain Phase
  • Actions On Objectives
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes WHERE ("Processes.process_name"="net*.exe" "Processes.process"="*stop \"samss\"*") BY Processes.dest Processes.user Processes.process Processes.process_guid Processes.process_name 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
| `windows_security_account_manager_stopped_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_security_account_manager_stopped_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
  • Processes.process_name
  • Processes.process
  • Processes.dest
  • Processes.user

How To Implement

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

SAM is a critical windows service, stopping it would cause major issues on an endpoint this makes false positive rare. AlthoughNo false positives have been identified.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
70.0 70 100 The Windows Security Account Manager (SAM) was stopped via cli by $user$ on $dest$ by this command: $process$

: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.

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: 3