Windows Disable LogOff Button Through Registry
Description
The following analytic detects a suspicious registry modification that disables the logoff feature on a Windows host. It leverages data from the Endpoint.Registry data model to identify changes to specific registry values associated with logoff functionality. This activity is significant because it can indicate ransomware attempting to make the compromised host unusable and hinder remediation efforts. If confirmed malicious, this action could prevent users from logging off, complicate incident response, and allow attackers to maintain persistence and control over the affected system.
Query · spl
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\Explorer\\*" Registry.registry_value_name IN ("NoLogOff", "StartMenuLogOff") Registry.registry_value_data = "0x00000001") by Registry.action Registry.dest Registry.process_guid Registry.process_id Registry.registry_hive Registry.registry_path Registry.registry_key_name Registry.registry_value_data Registry.registry_value_name Registry.registry_value_type Registry.status Registry.user Registry.vendor_product | `drop_dm_object_name(Registry)` | where isnotnull(registry_value_data) | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_disable_logoff_button_through_registry_filter`
Implementation guide
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
- This windows feature may implement by administrator in some server where shutdown is critical. In that scenario filter of machine and users that can modify this registry is needed.
Analyst notes
Known false positives: This windows feature may implement by administrator in some server where shutdown is critical. In that scenario filter of machine and users that can modify this registry is needed.