Detection: Disable Windows SmartScreen Protection

Updated Date: 2024-12-08 ID: 664f0fd0-91ff-11eb-a56f-acde48001122 Author: Teoderick Contreras, Splunk, Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects modifications to the Windows registry that disable SmartScreen protection. It leverages data from the Endpoint.Registry data model, specifically monitoring changes to registry paths associated with SmartScreen settings. This activity is significant because SmartScreen provides an early warning system against phishing and malware. Disabling it can indicate malicious intent, often seen in Remote Access Trojans (RATs) to evade detection while downloading additional payloads. If confirmed malicious, this action could allow attackers to bypass security measures, increasing the risk of successful phishing attacks and malware infections.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry WHERE Registry.registry_path IN ("*\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\SmartScreenEnabled", "*\\Microsoft\\Windows\\System\\EnableSmartScreen") Registry.registry_value_data  IN ("Off", "0") BY Registry.dest Registry.user Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
3| `drop_dm_object_name(Registry)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `disable_windows_smartscreen_protection_filter`

Data Source

Name Platform Sourcetype Source
Sysmon EventID 12 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Sysmon EventID 13 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
disable_windows_smartscreen_protection_filter search *
disable_windows_smartscreen_protection_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
Exploitation
DE.CM
CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search, you need to be ingesting logs with the registry value name, registry path, and registry value data from your endpoints. If you are using Sysmon, you must have at least version 2.0 of the official Sysmon TA. https://splunkbase.splunk.com/app/5709

Known False Positives

admin or user may choose to disable this windows features.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

The Windows Smartscreen was disabled on $dest$ by $user$.

Risk Object Risk Object Type Risk Score Threat Objects
user user 25 No Threat Objects
dest system 25 No Threat Objects

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational XmlWinEventLog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational XmlWinEventLog

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: GitHub | Version: 9