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Description

The following analytic identifies a modification in the Windows registry to change or disable Windows Defender smartscreen app install control. Microsoft Edge's App Install Control feature helps manage the installation of web-based applications. When attackers modify "ConfigureAppInstallControlEnabled" to 0, they are likely attempting to disable the App Install Control feature in Microsoft Edge. This change might allow users to bypass restrictions imposed by the browser on the installation of web-based applications. Disabling this feature might increase the risk of users being able to install potentially malicious or untrusted web applications without restrictions or controls imposed by the browser. This action could potentially lead to security vulnerabilities or compromise if users inadvertently install harmful applications.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-01-08
  • Author: Teoderick Contreras, Splunk
  • ID: c54b7439-cfb1-44c3-bb35-b0409553077c

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\\Windows Defender\\SmartScreen\\ConfigureAppInstallControl" Registry.registry_value_data= "Anywhere") OR (Registry.registry_path= "*\\Microsoft\\Windows Defender\\SmartScreen\\ConfigureAppInstallControlEnabled" 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_configure_app_install_control_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_impair_defense_configure_app_install_control_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 Define Windows Defender App Install Control registry set to disable 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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