ID | Technique | Tactic |
---|---|---|
T1112 | Modify Registry | Defense Evasion |
Detection: Windows Modify Registry AuthenticationLevelOverride
Description
The following analytic detects modifications to the Windows registry key "AuthenticationLevelOverride" within the Terminal Server Client settings. It leverages data from the Endpoint.Registry datamodel to identify changes where the registry value is set to 0x00000000. This activity is significant as it may indicate an attempt to override authentication levels for remote connections, a tactic used by DarkGate malware for malicious installations. If confirmed malicious, this could allow attackers to gain unauthorized remote access, potentially leading to data exfiltration or further system compromise.
Search
1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Registry where Registry.registry_path = "*\\Terminal Server Client\\AuthenticationLevelOverride" 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
3| `drop_dm_object_name(Registry)`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `windows_modify_registry_authenticationleveloverride_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Sysmon EventID 12 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' |
Sysmon EventID 13 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' |
Macros Used
Name | Value |
---|---|
security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
windows_modify_registry_authenticationleveloverride_filter | search * |
windows_modify_registry_authenticationleveloverride_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Risk Event | True |
Implementation
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. Also make sure that this registry was included in your config files ex. sysmon config to be monitored.
Known False Positives
Administrators may enable or disable this feature that may cause some false positive, however is not common. Filter as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
the registry for authentication level settings was modified on $dest$. | 49 | 70 | 70 |
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: 3