Detection: Windows Disable LogOff Button Through Registry

Updated Date: 2024-09-30 ID: b2fb6830-9ed1-11ec-9fcb-acde48001122 Author: Steven Dick, Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

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.

Search

1
2| tstats `security_content_summariesonly` count 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 _time span=1h Registry.dest Registry.user Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
3| `drop_dm_object_name(Registry)` 
4| where isnotnull(registry_value_data) 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `windows_disable_logoff_button_through_registry_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_disable_logoff_button_through_registry_filter	`search *`

windows_disable_logoff_button_through_registry_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1112	Modify Registry	Defense Evasion

KillChainPhase.EXPLOITAITON

NistCategory.DE_AE

Cis18Value.CIS_10

APT19

APT32

APT38

APT41

Aquatic Panda

Blue Mockingbird

Dragonfly

Earth Lusca

Ember Bear

FIN8

Gamaredon Group

Gorgon Group

Indrik Spider

Kimsuky

LuminousMoth

Magic Hound

Patchwork

Saint Bear

Silence

TA505

Threat Group-3390

Turla

Volt Typhoon

Wizard Spider

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

This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

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 offical 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.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Registry modification in "NoLogOff" on $dest$	49	70	70

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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: 5