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The following analytic identifies a modification in the Windows registry to define the threat action of Windows Defender. The ThreatSeverityDefaultAction registry setting in Windows Defender is used to define the default action taken by Windows Defender when it encounters threats of specific severity levels. A setting like ThreatSeverityDefaultAction is designed to define how Windows Defender responds to threats based on their severity. For example, it might determine whether Windows Defender quarantines, removes, or takes other actions against threats based on their severity levels. In this context, a registry value of 1 typically indicates an action to "clean," aiming to disinfect or resolve the detected threat, while a registry value of 9 signifies "no action," meaning that the antivirus software refrains from taking immediate steps against the identified threat.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-01-08
  • Author: Teoderick Contreras, Splunk
  • ID: 7215831c-8252-4ae3-8d43-db588e82f952




ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Kill Chain Phase
  • Exploitation
  • DE.CM
  • CIS 10
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry where Registry.registry_path= "*\\Windows Defender\\Threats\\ThreatSeverityDefaultAction*" Registry.registry_value_data IN ("0x00000001", "9") 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_define_win_defender_threat_action_filter`


The SPL above uses the following Macros:

:information_source: windows_impair_defense_define_win_defender_threat_action_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


Risk Score Impact Confidence Message
49.0 70 70 Define Windows Defender threat action through registry 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.


Test Dataset

Replay any dataset to Splunk Enterprise by using our tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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