MaxPatrol SIEM

Detects cyberincidents that undermine cyber resilience of a company

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

IDDS0022Data source and componentFile: File AccessDescription

Monitor for attempts to access SYSVOL that involve searching for XML files.

IDDS0017Data source and componentCommand: Command ExecutionDescription

Monitor executed commands and arguments that may search for SYSVOL data and/or GPP XML files, especially on compromised domain controllers.

Mitigation

IDM1047NameAuditDescription

Search SYSVOL for any existing GGPs that may contain credentials and remove them.

IDM1051NameUpdate SoftwareDescription

Apply patch KB2962486 which prevents credentials from being stored in GPPs.

IDM1015NameActive Directory ConfigurationDescription

Remove vulnerable Group Policy Preferences.