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Description

The following analytic identifies a modification in the Windows registry to override windows defender smartscreen prompt. The "PreventSmartScreenPromptOverride" registry setting is associated with the Windows SmartScreen feature, specifically related to controlling whether users can override SmartScreen prompts. When attackers modify "PreventSmartScreenPromptOverride" to 0, it signifies an attempt to disable the prevention of user overrides for SmartScreen prompts. By doing so, attackers aim to allow users to bypass or ignore SmartScreen warnings or prompts. This change increases the risk by permitting users to disregard warnings about potentially unsafe or malicious files or websites that would typically trigger SmartScreen alerts. It could lead to users unintentionally executing or accessing malicious content, potentially resulting in security incidents or system compromises.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-01-08
  • Author: Teoderick Contreras, Splunk
  • ID: 08058866-7987-486f-b042-275715ef6e9d

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 FROM datamodel=Endpoint.Registry WHERE Registry.registry_path= "*\\Microsoft\\Edge\\PreventSmartScreenPromptOverride" Registry.registry_value_data= "0x00000000" BY _time span=1h Registry.dest Registry.user Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
| `drop_dm_object_name(Registry)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_impair_defense_override_smartscreen_prompt_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_impair_defense_override_smartscreen_prompt_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 SmartScreen prompt was override 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

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