Detection: Windows Group Policy Object Created

Updated Date: 2024-05-17 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.

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 Supported App
Windows Event Log Security 5136 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Security' N/A

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
Cinnamon Tempest
Indrik Spider
APT3
APT5
Chimera
Cinnamon Tempest
Indrik Spider
Magic Hound
Naikon
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: 2