ID | Technique | Tactic |
---|---|---|
T1484 | Domain or Tenant Policy Modification | Defense Evasion |
T1484.001 | Group Policy Modification | Privilege Escalation |
Detection: Windows Admon Default Group Policy Object Modified
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.
Search
1`admon` admonEventType=Update objectCategory="CN=Group-Policy-Container,CN=Schema,CN=Configuration,DC=*" (displayName="Default Domain Policy" OR displayName="Default Domain Controllers Policy")
2| stats min(_time) as firstTime max(_time) as lastTime values(gPCFileSysPath) by dcName, displayName
3| `security_content_ctime(firstTime)`
4| `security_content_ctime(lastTime)`
5| `windows_admon_default_group_policy_object_modified_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
Windows Active Directory Admon | Windows | 'ActiveDirectory' |
'ActiveDirectory' |
N/A |
Macros Used
Name | Value |
---|---|
admon | source=ActiveDirectory |
windows_admon_default_group_policy_object_modified_filter | search * |
windows_admon_default_group_policy_object_modified_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 |
Implementation
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
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
A default domain group policy was updated on $dcName$ | 50 | 100 | 50 |
References
-
https://www.trustedsec.com/blog/weaponizing-group-policy-objects-access/
-
https://docs.splunk.com/Documentation/SplunkCloud/8.1.2101/Data/MonitorActiveDirectory
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | ActiveDirectory |
ActiveDirectory |
Integration | ✅ Passing | Dataset | ActiveDirectory |
ActiveDirectory |
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: 3