Detection: Windows Group Policy Object Created

Updated Date: 2024-09-30 ID: 23add2a8-ea22-4fd4-8bc0-8c0b822373a1 Author: Mauricio Velazco Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of a new Group Policy Object (GPO) by leveraging Event IDs 5136 and 5137. This detection uses directory service change events to identify when a new GPO is created. Monitoring GPO creation is crucial as adversaries can exploit GPOs to escalate privileges or deploy malware across an Active Directory network. If confirmed malicious, this activity could allow attackers to control system configurations, deploy ransomware, or propagate malware, leading to widespread compromise and significant operational disruption.

Search

1`wineventlog_security` EventCode=5137 OR (EventCode=5136 AttributeValue!="New Group Policy Object" AND (AttributeLDAPDisplayName=displayName OR AttributeLDAPDisplayName=gPCFileSysPath) ) ObjectClass=groupPolicyContainer 
2| stats values(AttributeValue) as details values(SubjectUserSid) as User values(ObjectDN) as ObjectDN by ObjectGUID Computer 
3| eval GPO_Name = mvindex(details, 0) 
4| eval GPO_Path = mvindex(details, 1) 
5| fields - details 
6| `windows_group_policy_object_created_filter`

Data Source

Name	Platform	Sourcetype	Source
Windows Event Log Security 5136	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`
Windows Event Log Security 5137	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`

Macros Used

Name	Value
wineventlog_security	`eventtype=wineventlog_security OR Channel=security OR source=XmlWinEventLog:Security`
windows_group_policy_object_created_filter	`search *`

windows_group_policy_object_created_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
T1484	Domain or Tenant Policy Modification	Defense Evasion
T1484.001	Group Policy Modification	Privilege Escalation
T1078.002	Domain Accounts	Defense Evasion

KillChainPhase.DELIVERY

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_CM

Cis18Value.CIS_10

APT41

Cinnamon Tempest

Indrik Spider

APT3

APT5

Agrius

Aquatic Panda

Chimera

Cinnamon Tempest

Indrik Spider

Magic Hound

Naikon

Play

Sandworm Team

TA505

Threat Group-1314

ToddyCat

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 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, the Advanced Security Audit policy setting Audit Directory Service Changes within DS Access needs to be enabled. Furthermore, the appropriate system access control lists (SACL) need to be created as the used events are not logged by default. A good guide to accomplish this can be found here https://jgspiers.com/audit-group-policy-changes/.

Known False Positives

Group Policy Objects are created as part of regular administrative operations, filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
A new group policy objected was created by $User$	40	80	50

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:Security`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Security`	`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: 4