Techniques
Sample rules
Windows Default Group Policy Object Modified with GPME
- source: splunk
- technicques:
- T1484
- T1484.001
Description
The following analytic leverages the Endpoint datamodel to identify the potential edition of a default Group Policy Object. A fresh installation of an Active Directory network will typically contain two default group policy objects Default Domain Controllers Policy and Default Domain Policy. The default domain controllers policy is used to enforce and set policies to all the domain controllers within the domain environment. The default domain policy is linked to all users and computers by default. An adversary who has obtained privileged access to an Active Directory network may modify the default group policy objects to obtain further access, deploy persistence or execute malware across a large number of hosts. Security teams should monitor the edition of the default GPOs.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=mmc.exe (Processes.process =*gpme.msc*) AND (Processes.process = "*31B2F340-016D-11D2-945F-00C04FB984F9*" OR Processes.process = "*6AC1786C-016F-11D2-945F-00C04fB984F9*" ) by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_default_group_policy_object_modified_with_gpme_filter`
Windows Default Group Policy Object Modified
- source: splunk
- technicques:
- T1484
- T1484.001
Description
The following analytic leverages Event ID 5136 to identify the modification of a default Group Policy Object. A fresh installation of an Active Directory network will typically contain two default group policy objects Default Domain Controllers Policy and Default Domain Policy. The default domain controllers policy is used to enforce and set policies to all the domain controllers within the domain environment. The default domain policy is linked to all users and computers by default. An adversary who has obtained privileged access to an Active Directory network may modify the default group policy objects to obtain further access, deploy persistence or execute malware across a large number of hosts. Security teams should monitor the modification of the default GPOs.
Detection logic
`wineventlog_security` EventCode=5136 ObjectClass=groupPolicyContainer AttributeLDAPDisplayName=versionNumber (ObjectDN="CN={31B2F340-016D-11D2-945F-00C04FB984F9},CN=POLICIES,CN=SYSTEM,DC=*" OR ObjectDN="CN={6AC1786C-016F-11D2-945F-00C04fB984F9},CN=POLICIES,CN=SYSTEM,DC=*")
| stats min(_time) as firstTime max(_time) as lastTime by ObjectDN SubjectUserSid AttributeValue Computer DSName
| rename AttributeValue as versionNumber
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_default_group_policy_object_modified_filter`
Windows Admon Default Group Policy Object Modified
- source: splunk
- technicques:
- T1484
- T1484.001
Description
The following analytic leverages Splunks Admon to identify the modification of a default Group Policy Object. A fresh installation of an Active Directory network will typically contain two default group policy objects Default Domain Controllers Policy and Default Domain Policy. The default domain controllers policy is used to enforce and set policies to all the domain controllers within the domain environment. The default domain policy is linked to all users and computers by default. An adversary who has obtained privileged access to an Active Directory network may modify the default group policy objects to obtain further access, deploy persistence or execute malware across a large number of hosts. Security teams should monitor the modification of the default GPOs.
Detection logic
`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`