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Description

This analytic is to detect a suspicious modification of registry to disable UAC remote restriction. This technique was well documented in Microsoft page where attacker may modify this registry value to bypassed UAC feature of windows host. This is a good indicator that some tries to bypassed UAC to suspicious process or gain privilege escalation.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
  • Last Updated: 2022-01-27
  • Author: Teoderick Contreras, Splunk
  • ID: 9928b732-210e-11ec-b65e-acde48001122

Annotations

ATT&CK
ID Technique Tactic
T1548.002 Bypass User Account Control Defense Evasion, Privilege Escalation
T1548 Abuse Elevation Control Mechanism Defense Evasion, Privilege Escalation
Kill Chain Phase
  • Exploitation
NIST
CIS20
CVE
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| tstats `security_content_summariesonly` count  min(_time) as firstTime max(_time) as lastTime 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.dest Registry.user Registry.registry_path Registry.registry_value_name Registry.registry_value_data Registry.process_guid 
| `drop_dm_object_name(Registry)` 
|rename process_guid as proc_guid 
|join proc_guid, _time [
| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes by _time span=1h Processes.process_id Processes.process_name Processes.process Processes.dest Processes.parent_process_name Processes.parent_process Processes.process_guid 
| `drop_dm_object_name(Processes)` 
|rename process_guid as proc_guid 
| fields _time dest user parent_process_name parent_process process_name process_path process proc_guid registry_path registry_value_name registry_value_data] 
| table _time dest user parent_process_name parent_process process_name process_path process proc_guid registry_path registry_value_name registry_value_data 
| `disable_uac_remote_restriction_filter`

Macros

The SPL above uses the following Macros:

Note that 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 field

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

How To Implement

To successfully implement this search, you must be ingesting data that records registry activity from your hosts to populate the endpoint data model in the registry node. This is typically populated via endpoint detection-and-response product, such as Carbon Black or endpoint data sources, such as Sysmon. The data used for this search is typically generated via logs that report reads and writes to the registry.

Known False Positives

admin may set this policy for non-critical machine.

Associated Analytic story

RBA

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

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

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