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Description

The following analytic detects the disabling of Windows Update services, such as "Update Orchestrator Service for Windows Update," "WaaSMedicSvc," and "Windows Update." It leverages Windows System Event ID 7040 logs to identify changes in service start modes to 'disabled.' This activity is significant as it can indicate an adversary's attempt to evade defenses by preventing critical updates, leaving the system vulnerable to exploits. If confirmed malicious, this could allow attackers to maintain persistence and exploit unpatched vulnerabilities, compromising the integrity and security of the affected host.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-20
  • Author: Teoderick Contreras, Splunk
  • ID: 0dc25c24-6fcf-456f-b08b-dd55a183e4de

Annotations

ATT&CK

ATT&CK

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


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`wineventlog_system` EventCode=7040 (service_name IN ("Update Orchestrator Service for Windows Update", "WaaSMedicSvc", "Windows Update") OR param1 IN ("UsoSvc", "WaaSMedicSvc", "wuauserv")) AND (param3=disabled OR start_mode = disabled) 
| stats count min(_time) as firstTime max(_time) as lastTime by Computer Error_Code service_name start_mode param1 param2 param3 param4 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_service_stop_win_updates_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_service_stop_win_updates_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
  • Computer
  • EventCode
  • Error_Code
  • service_name
  • start_mode
  • param1
  • param2
  • param3
  • param4

How To Implement

To successfully implement this search, you need to be ingesting logs with the Service name, Service File Name Service Start type, and Service Type from your endpoints (like Windows system.log Event ID 7040)

Known False Positives

Network administrator may disable this services as part of its audit process within the network. Filter is needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 Windows update services $service_name$ was being disabled on $dest$

: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