Windows Impair Defense Change Win Defender Quick Scan Interval
Description
The following analytic detects modifications to the Windows registry that change the Windows Defender Quick Scan Interval. It leverages data from the Endpoint.Registry data model, focusing on changes to the "QuickScanInterval" registry path. This activity is significant because altering the scan interval can impair Windows Defender's ability to detect malware promptly, potentially allowing threats to persist undetected. If confirmed malicious, this modification could enable attackers to bypass security measures, maintain persistence, and execute further malicious activities without being detected by quick scans.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2024-05-27
- Author: Teoderick Contreras, Splunk
- ID: 783f0798-f679-4c17-b3b3-187febf0b9b8
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
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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\\Scan\\QuickScanInterval" 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_change_win_defender_quick_scan_interval_filter`
Macros
The SPL above uses the following Macros:
windows_impair_defense_change_win_defender_quick_scan_interval_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 QuickScanInterval feature was modified on $dest$. |
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
- https://x.com/malmoeb/status/1742604217989415386?s=20
- https://github.com/undergroundwires/privacy.sexy
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: 2