Disable UAC Remote Restriction

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Description

The following analytic detects the modification of the registry to disable UAC remote restriction by setting the "LocalAccountTokenFilterPolicy" value to "0x00000001". It leverages data from the Endpoint.Registry data model, specifically monitoring changes to the registry path "\CurrentVersion\Policies\System". This activity is significant because disabling UAC remote restriction can allow an attacker to bypass User Account Control (UAC) protections, potentially leading to privilege escalation. If confirmed malicious, this could enable an attacker to execute unauthorized actions with elevated privileges, compromising the security of the affected system.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2024-05-24
• Author: Steven Dick, Teoderick Contreras, Splunk
• ID: 9928b732-210e-11ec-b65e-acde48001122

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1548.002	Bypass User Account Control	Privilege Escalation, Defense Evasion

T1548

Abuse Elevation Control Mechanism

Privilege Escalation, Defense Evasion

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path="*\\CurrentVersion\\Policies\\System*" Registry.registry_value_name="LocalAccountTokenFilterPolicy" Registry.registry_value_data="0x00000001"  ) BY _time span=1h Registry.user Registry.dest Registry.registry_path Registry.registry_key_name Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
| `drop_dm_object_name(Registry)`
| where isnotnull(registry_value_data) 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `disable_uac_remote_restriction_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• security_content_summariesonly

disable_uac_remote_restriction_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.

• _time
• Registry.dest
• Registry.registry_value_name
• Registry.registry_key_name
• Registry.registry_path
• Registry.registry_value_data
• Registry.process_guid

How To Implement

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

admin may set this policy for non-critical machine.

Associated Analytic Story

• Suspicious Windows Registry Activities
• Windows Defense Evasion Tactics
• CISA AA23-347A
• Windows Registry Abuse

RBA

Risk Score	Impact	Confidence	Message
80.0	80	100	Modified/added/deleted registry entry $registry_path$ in $dest$

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://docs.microsoft.com/en-us/troubleshoot/windows-server/windows-security/user-account-control-and-remote-restriction

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: 5