splunk_escuHunting

Windows Modify Registry wuStatusServer

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.

Detection Query

| 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.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product | `drop_dm_object_name(Registry)` | `security_content_ctime(lastTime)` | `security_content_ctime(firstTime)` | `windows_modify_registry_wustatusserver_filter`

Author

Teoderick Contreras, Splunk

Data Sources

Sysmon EventID 13

References

https://learn.microsoft.com/de-de/security-updates/windowsupdateservices/18127499

Raw Content

name: Windows Modify Registry wuStatusServer
id: 073e69d0-68b2-4142-aa90-a7ee6f590676
version: 9
creation_date: '2023-04-26'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Hunting
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.
data_source:
    - Sysmon EventID 13
search: '| 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.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product | `drop_dm_object_name(Registry)` | `security_content_ctime(lastTime)` | `security_content_ctime(firstTime)` | `windows_modify_registry_wustatusserver_filter`'
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.
references:
    - https://learn.microsoft.com/de-de/security-updates/windowsupdateservices/18127499
analytic_story:
    - RedLine Stealer
asset_type: Endpoint
mitre_attack_id:
    - T1112
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/redline/modify_registry/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit