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Description

The following analytic leverages Event IDs 5136 and 51137 to identify the creation of a new Group Policy Object. With GPOs, system administrators can manage and configure applications, software operations, and user settings throughout an entire organization. GPOs can be abused and leveraged by adversaries to escalate privileges or deploy malware across an Active Directory network. As an example, the Lockbit ransomware malware will create new group policies on the domain controller that are then pushed out to every device on the network. Security teams should monitor the creation of new Group Policy Objects.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-03-27
  • Author: Mauricio Velazco
  • ID: 23add2a8-ea22-4fd4-8bc0-8c0b822373a1

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1484 Domain Policy Modification Defense Evasion, Privilege Escalation
T1484.001 Group Policy Modification Defense Evasion, Privilege Escalation
T1078.002 Domain Accounts Defense Evasion, Persistence, Privilege Escalation, Initial Access
Kill Chain Phase
  • Exploitation
  • Installation
  • Delivery
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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

Macros

The SPL above uses the following Macros:

:information_source: windows_group_policy_object_created_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • EventCode
  • AttributeValue
  • AttributeLDAPDisplayName
  • ObjectClass
  • SubjectUserSid
  • ObjectDN
  • ObjectGUID
  • Computer

How To Implement

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

RBA

Risk Score Impact Confidence Message
40.0 80 50 A new group policy objected was created by $User$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

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

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