Detection: Windows Registry Modification for Safe Mode Persistence

Updated Date: 2024-05-20 ID: c6149154-c9d8-11eb-9da7-acde48001122 Author: Teoderick Contreras, Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies modifications to the SafeBoot registry keys, specifically within the Minimal and Network paths. This detection leverages registry activity logs from endpoint data sources like Sysmon or EDR tools. Monitoring these keys is crucial as adversaries can use them to persist drivers or services in Safe Mode, with Network allowing network connections. If confirmed malicious, this activity could enable attackers to maintain persistence even in Safe Mode, potentially bypassing certain security measures and facilitating further malicious actions.

Search

1
2| tstats `security_content_summariesonly` count from datamodel=Endpoint.Registry where Registry.registry_path IN ("*SYSTEM\\CurrentControlSet\\Control\\SafeBoot\\Minimal\\*","*SYSTEM\\CurrentControlSet\\Control\\SafeBoot\\Network\\*") by _time span=1h Registry.dest Registry.user Registry.registry_path Registry.registry_value_name Registry.process_guid Registry.registry_key_name Registry.registry_value_data 
3| `drop_dm_object_name(Registry)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_registry_modification_for_safe_mode_persistence_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Sysmon EventID 12	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($field$)`
windows_registry_modification_for_safe_mode_persistence_filter	`search *`

windows_registry_modification_for_safe_mode_persistence_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
T1547.001	Registry Run Keys / Startup Folder	Persistence
T1547	Boot or Logon Autostart Execution	Privilege Escalation

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_CM

Cis18Value.CIS_10

APT18

APT19

APT28

APT29

APT3

APT32

APT33

APT37

APT39

APT41

BRONZE BUTLER

Cobalt Group

Confucius

Dark Caracal

Darkhotel

Dragonfly

FIN10

FIN13

FIN6

FIN7

Gamaredon Group

Gorgon Group

Higaisa

Inception

Ke3chang

Kimsuky

Lazarus Group

LazyScripter

Leviathan

LuminousMoth

Magic Hound

Molerats

MuddyWater

Mustang Panda

Naikon

PROMETHIUM

Patchwork

Putter Panda

RTM

Rocke

Sidewinder

Silence

TA2541

TeamTNT

Threat Group-3390

Tropic Trooper

Turla

Windshift

Wizard Spider

ZIRCONIUM

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 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

updated windows application needed in safe boot may used this registry

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Safeboot registry $registry_path$ was added or modified with a new value $registry_value_name$ on $dest$	42	60	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