Detection: Windows Modify Registry Utilize ProgIDs

Updated Date: 2024-09-30 ID: 64fa82dd-fd11-472a-9e94-c221fffa591d Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic detects modifications to the Windows Registry specifically targeting Programmatic Identifier associations to bypass User Account Control (UAC) Windows OS feature. ValleyRAT may create or alter registry entries to targetted progIDs like .pwn files with malicious processes, allowing it to execute harmful scripts or commands when these files are opened. By monitoring for unusual changes in registry keys linked to ProgIDs, this detection enables security analysts to identify potential threats like ValleyRAT execution attempts. Early detection of these modifications helps mitigate unauthorized execution and prevents further exploitation of the system.

Search

1
2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Registry WHERE Registry.registry_path= "*\\ms-settings\\CurVer\\(Default)" BY 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| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_modify_registry_utilize_progids_filter`

Data Source

Name	Platform	Sourcetype	Source
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_modify_registry_utilize_progids_filter	`search *`

windows_modify_registry_utilize_progids_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 official Sysmon TA. https://splunkbase.splunk.com/app/5709

Known False Positives

unknown

Associated Analytic Story

ValleyRAT

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
A possible ValleyRAT Registry modification in [$dest$].	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: 3