Windows Impair Defense Delete Win Defender Context Menu
Description
The search looks for the deletion of Windows Defender context menu within the registry. This is consistent behavior with RAT malware across a fleet of endpoints. This particular behavior is executed when an adversary gains access to an endpoint and begins to perform execution. Usually, a batch (.bat) will be executed and multiple registry and scheduled task modifications will occur. During triage, review parallel processes and identify any further file modifications.
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-06-07
- Author: Teoderick Contreras, Splunk
- ID: 395ed5fe-ad13-4366-9405-a228427bdd91
Annotations
ATT&CK
Kill Chain Phase
- Delivery
NIST
- PR.PT
- DE.CM
CIS20
- CIS 8
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 = "*\\shellex\\ContextMenuHandlers\\EPP" Registry.action = deleted by Registry.registry_path Registry.registry_value_name Registry.registry_value_data Registry.process_guid Registry.action Registry.dest Registry.user
| `drop_dm_object_name(Registry)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_impair_defense_delete_win_defender_context_menu_filter`
Macros
The SPL above uses the following Macros:
windows_impair_defense_delete_win_defender_context_menu_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Supported Add-on (TA)
List of Splunk Add-on’s tested to work with the analytic.
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 |
---|---|---|---|
25.0 | 50 | 50 | Windows Defender context menu registry key deleted 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://blog.malwarebytes.com/malwarebytes-news/2021/02/lazyscripter-from-empire-to-double-rat/
- https://app.any.run/tasks/45f5d114-91ea-486c-ab01-41c4093d2861/
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: 1