Detection: Disabling SystemRestore In Registry

Updated Date: 2024-05-22 ID: f4f837e2-91fb-11eb-8bf6-acde48001122 Author: Steven Dick, Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the modification of registry keys to disable System Restore on a machine. It leverages data from the Endpoint.Registry data model, specifically monitoring changes to registry paths associated with System Restore settings. This activity is significant because disabling System Restore can hinder recovery efforts and is a tactic often used by Remote Access Trojans (RATs) to maintain persistence on an infected system. If confirmed malicious, this action could prevent system recovery, allowing the attacker to sustain their foothold and potentially cause further damage or data loss.

1
2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE (Registry.registry_path= "*\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\SystemRestore\\DisableSR" OR Registry.registry_path= "*\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\SystemRestore\\DisableConfig" OR Registry.registry_path= "*\\SOFTWARE\\Policies\\Microsoft\\Windows NT\\SystemRestore\\DisableSR" OR Registry.registry_path= "*\\SOFTWARE\\Policies\\Microsoft\\Windows NT\\SystemRestore\\DisableConfig" 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| `disabling_systemrestore_in_registry_filter`

Data Source

Name Platform Sourcetype Source Supported App
Sysmon EventID 12 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
disabling_systemrestore_in_registry_filter search *
disabling_systemrestore_in_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
T1490 Inhibit System Recovery Impact
KillChainPhase.ACTIONS_ON_OBJECTIVES
NistCategory.DE_CM
Cis18Value.CIS_10
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 Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

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

in some cases admin can disable systemrestore on a machine.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
The Windows registry was modified to disable system restore on $dest$ by $user$. 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 WinEventLog:Security WinEventLog
Integration ✅ Passing Dataset WinEventLog:Security WinEventLog

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: 6