Windows Impair Defenses Disable HVCI
Description
The following analytic detects the disabling of Hypervisor-protected Code Integrity (HVCI) by monitoring changes in the Windows registry. It leverages data from the Endpoint datamodel, specifically focusing on registry paths and values related to HVCI settings. This activity is significant because HVCI helps protect the kernel and system processes from tampering by malicious code. If confirmed malicious, disabling HVCI could allow attackers to execute unsigned kernel-mode code, potentially leading to kernel-level rootkits or other severe security breaches.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2024-05-24
- Author: Michael Haag, Splunk
- ID: b061dfcc-f0aa-42cc-a6d4-a87f172acb79
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
1
2
3
4
5
6
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Registry where Registry.registry_path = "*\\CurrentControlSet\\Control\\DeviceGuard\\Scenarios\\HypervisorEnforcedCodeIntegrity\\Enabled" Registry.registry_value_data="0x00000000" by Registry.registry_path Registry.registry_value_name Registry.registry_value_data Registry.process_guid Registry.action Registry.user Registry.dest
| `drop_dm_object_name(Registry)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_impair_defenses_disable_hvci_filter`
Macros
The SPL above uses the following Macros:
windows_impair_defenses_disable_hvci_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.
- Registry.registry_path
- Registry.registry_value_data
- Registry.registry_value_name
- Registry.process_guid
- Registry.action
- Registry.user
- Registry.dest
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. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
Known False Positives
False positives will be limited to administrative scripts disabling HVCI. Filter as needed.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
70.0 | 70 | 100 | HVCI has been disabled 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
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