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Description

The following analytic identifies a modification in the Windows registry to disable Windows Defender Scan On Update. The "DisableScanOnUpdate" registry setting in Windows Defender, when set to a value of 1, typically signifies the feature that prevents automatic scans from initiating when updates to Windows Defender or its antivirus definitions are installed. Any modifications to registry settings, it's important to ensure that changes align with security policies and best practices. Incorrect settings might affect the system's security or functionality. Always consider the implications and ensure changes are made based on accurate information and organizational requirements. This registry setting is being abuse by several threat actors, adversaries and red teamers to bypasses Windows defender detections.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint, Updates
  • Last Updated: 2024-01-08
  • Author: Teoderick Contreras, Splunk
  • ID: 0418e72f-e710-4867-b656-0688e1523e09

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Kill Chain Phase
  • Exploitation
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.Registry where Registry.registry_path= "*\\Windows Defender\\Signature Updates\\DisableScanOnUpdate" Registry.registry_value_data="0x00000001" by Registry.registry_key_name Registry.user Registry.registry_path Registry.registry_value_data Registry.action Registry.dest 
| `drop_dm_object_name(Registry)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_impair_defense_disable_win_defender_scan_on_update_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_impair_defense_disable_win_defender_scan_on_update_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_value_name
  • Registry.dest
  • Registry.user
  • Registry.registry_path
  • Registry.action

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 Registry node.

Known False Positives

It is unusual to turn this feature off a Windows system since it is a default security control, although it is not rare for some policies to disable it. Although no false positives have been identified, use the provided filter macro to tune the search.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 Windows Defender DisableScanOnUpdate feature set to enable 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: 1