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Description

The following analytic identifies suspicious modifications to the Windows Update configuration registry, specifically targeting the WUStatusServer key. It leverages data from the Endpoint datamodel to detect changes in the registry path associated with Windows Update settings. This activity is significant as it is commonly used by adversaries, including malware like RedLine Stealer, to bypass detection and deploy additional payloads. If confirmed malicious, this modification could allow attackers to evade defenses, potentially leading to further system compromise and persistent unauthorized access.

  • Type: Hunting
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-05-31
  • Author: Teoderick Contreras, Splunk
  • ID: 073e69d0-68b2-4142-aa90-a7ee6f590676

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1112 Modify Registry Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Registry where Registry.registry_path="*\\SOFTWARE\\Policies\\Microsoft\\Windows\\WindowsUpdate\\WUStatusServer" by Registry.dest Registry.user Registry.registry_path Registry.registry_value_data Registry.registry_key_name 
| `drop_dm_object_name(Registry)` 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
| `windows_modify_registry_wustatusserver_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_modify_registry_wustatusserver_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
  • Registry.registry_key_name
  • Registry.registry_path
  • Registry.user
  • Registry.dest
  • Registry.registry_value_name
  • Registry.action
  • Registry.registry_value_data

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

administrators may enable or disable this feature that may cause some false positive.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 a registry modification in Windows auto update configuration in $dest$

: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.

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: 2