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Description

The following analytic detects modifications to the default Group Policy Objects (GPOs) in an Active Directory environment. It leverages Splunk's Admon to monitor updates to the "Default Domain Policy" and "Default Domain Controllers Policy." This activity is significant because changes to these default GPOs can indicate an adversary with privileged access attempting to gain further control, establish persistence, or deploy malware across multiple hosts. If confirmed malicious, such modifications could lead to widespread policy enforcement changes, unauthorized access, and potential compromise of the entire domain environment.

  • Type: TTP

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

  • Last Updated: 2024-05-28
  • Author: Mauricio Velazco, Splunk
  • ID: 83458004-db60-4170-857d-8572f16f070b

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1484 Domain or Tenant Policy Modification Defense Evasion, Privilege Escalation
T1484.001 Group Policy Modification Defense Evasion, Privilege Escalation
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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 `admon` admonEventType=Update objectCategory="CN=Group-Policy-Container,CN=Schema,CN=Configuration,DC=*" (displayName="Default Domain Policy" OR displayName="Default Domain Controllers Policy") 
| stats min(_time) as firstTime max(_time) as lastTime values(gPCFileSysPath) by dcName, displayName 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_admon_default_group_policy_object_modified_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_admon_default_group_policy_object_modified_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
  • admonEventType
  • objectCategory
  • displayName
  • gPCFileSysPath
  • dcName

How To Implement

To successfully implement this search, you need to be monitoring Active Directory logs using Admon. Details can be found here https://docs.splunk.com/Documentation/SplunkCloud/8.1.2101/Data/MonitorActiveDirectory

Known False Positives

The default Group Policy Objects within an AD network may be legitimately updated for administrative operations, filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
50.0 100 50 A default domain group policy was updated on $dcName$

: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

source | version: 2