T1552.006: Group Policy Preferences
Adversaries may attempt to find unsecured credentials in Group Policy Preferences (GPP). GPP are tools that allow administrators to create domain policies with embedded credentials. These policies allow administrators to set local accounts.
These group policies are stored in SYSVOL on a domain controller. This means that any domain user can view the SYSVOL share and decrypt the password (using the AES key that has been made public).
The following tools and scripts can be used to gather and decrypt the password file from Group Policy Preference XML files:
- Metasploit’s post exploitation module:
post/windows/gather/credentials/gpp
- Get-GPPPassword
- gpprefdecrypt.py
On the SYSVOL share, adversaries may use the following command to enumerate potential GPP XML files: dir /s * .xml
Positive Technologies products that cover the technique
MaxPatrol SIEM knowledge base
mitre_attck_cred_access: PT-CR-898: Access_to_Files_Containing_Passwords: Access to files that can contain credentials
Detection
ID | DS0022 | Data source and component | File: File Access | Description | Monitor for attempts to access SYSVOL that involve searching for XML files. |
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ID | DS0017 | Data source and component | Command: Command Execution | Description | Monitor executed commands and arguments that may search for SYSVOL data and/or GPP XML files, especially on compromised domain controllers. |
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Mitigation
ID | M1047 | Name | Audit | Description | Search SYSVOL for any existing GGPs that may contain credentials and remove them. |
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ID | M1051 | Name | Update Software | Description | Apply patch KB2962486 which prevents credentials from being stored in GPPs. |
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ID | M1015 | Name | Active Directory Configuration | Description | Remove vulnerable Group Policy Preferences. |
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