Group Policy Discovery (T1615)
Group Policy Discovery [T1615]
Last updated
Group Policy Discovery [T1615]
Last updated
Name: Group Policy Discovery
ID: T1615
Tactics:
Group Policy Discovery (Technique ID: T1615) is a reconnaissance technique listed in the MITRE ATT&CK framework under the tactic "Discovery." Attackers utilize this method to identify and analyze Group Policy Objects (GPOs) within Windows Active Directory environments. GPOs define security settings, software installation policies, user permissions, and other configurations. By discovering and analyzing these policies, adversaries can gather valuable intelligence about the organization's security posture, network structure, and potential vulnerabilities.
Group Policy Discovery involves enumerating and examining Group Policy Objects to understand their content and scope within Active Directory environments. Attackers commonly perform this technique through built-in Windows tools, scripts, or third-party utilities.
Key technical details include:
Group Policy Objects (GPOs):
GPOs are stored in two locations:
Active Directory database: Contains metadata and links to organizational units (OUs), sites, or domains.
SYSVOL share: Contains actual policy files, scripts, and configuration settings.
Attackers typically access the SYSVOL share (\\<DOMAIN>\SYSVOL) to enumerate policy files.
Execution Methods:
Built-in Windows commands:
gpresult: Displays applied policies and resultant set of policies.
net share: Lists network shares, including SYSVOL.
dir: Enumerates policy files in the SYSVOL directory.
PowerShell commands:
Third-party tools and scripts:
BloodHound (for visualizing AD environment and GPO relationships)
PowerView (PowerShell-based reconnaissance framework)
Information Gathered:
Security settings (password policies, account lockout settings)
User permissions and privileges
Software deployment policies
Network and firewall configurations
Logon/logoff scripts
Attackers commonly leverage Group Policy Discovery across multiple stages of the attack lifecycle, particularly during initial reconnaissance, lateral movement, and privilege escalation phases:
Initial Reconnaissance:
Identifying security posture and defensive measures.
Understanding domain-wide policies and restrictions.
Privilege Escalation:
Finding misconfigured GPOs that grant excessive permissions or privileges.
Discovering scripts or applications deployed via GPO that can be exploited.
Lateral Movement and Persistence:
Determining how software or scripts are pushed across the domain.
Identifying opportunities to deploy malicious scripts or backdoors through compromised GPOs.
Pre-Attack Planning:
Mapping network structure and administrative boundaries.
Identifying high-value targets based on applied policies.
Detection of Group Policy Discovery involves monitoring specific behaviors, events, and indicators of compromise, including:
Event Log Monitoring:
Windows Security Logs:
Event ID 4663 (An attempt was made to access an object) on SYSVOL share.
Event ID 5140 (Network share object accessed).
Monitoring for unusual access patterns to SYSVOL shares.
Network Traffic Analysis:
Monitoring SMB/CIFS traffic to domain controllers and SYSVOL shares.
Detecting unusual enumeration or file access attempts.
Endpoint Detection and Response (EDR):
Identifying execution of reconnaissance commands (gpresult, net share, dir \\SYSVOL).
Detecting usage of PowerShell scripts or third-party enumeration tools like PowerView or BloodHound.
SIEM and Centralized Logging Solutions:
Correlating events from multiple sources to detect anomalous access patterns.
Creating alerts for repeated or unexpected access to Group Policy files.
Indicators of Compromise (IoCs):
Unusual access timestamps on GPO files.
Execution of known reconnaissance scripts or tools.
Presence of unauthorized GPO backups or exported policy reports.
Early detection of Group Policy Discovery is critical due to the potential severe impacts and threats posed by adversaries who leverage this technique:
Security Posture Exposure:
Attackers gain insight into organizational security configurations, enabling them to identify weaknesses and vulnerabilities.
Privilege Escalation Opportunities:
Misconfigured or overly permissive GPOs can be exploited to escalate privileges or gain administrative rights.
Lateral Movement Enablement:
Understanding GPO deployment mechanisms allows attackers to move laterally within a network, spreading malware or establishing persistence.
Persistence and Backdoor Deployment:
Attackers may manipulate GPOs to deploy malicious scripts or software across multiple endpoints, establishing widespread persistence.
Data Exfiltration Risks:
Compromised GPOs can facilitate data exfiltration by altering firewall or security settings, reducing detection capabilities.
Early detection allows organizations to:
Quickly respond and limit damage.
Prevent privilege escalation and lateral movement.
Strengthen security posture by remediating misconfigured policies.
Reduce overall risk of compromise and data breaches.
Real-world examples and scenarios involving Group Policy Discovery include:
APT29 (Cozy Bear):
Known to use built-in Windows commands (gpresult, net share) and PowerShell scripts to enumerate Active Directory GPOs.
Utilized GPO discovery to map network defenses and identify security configurations, facilitating further exploitation and lateral movement.
FIN7 Cybercrime Group:
Leveraged Group Policy Discovery to identify software deployment policies and security configurations.
Exploited misconfigured GPOs to deploy malware across victim networks, enabling persistence and data exfiltration.
BloodHound Tool:
BloodHound is frequently used by penetration testers and attackers to visualize Active Directory environments, including GPOs.
Attackers utilize BloodHound to map GPO relationships, identify high-value targets, and discover privilege escalation paths.
PowerSploit's PowerView Module:
Attackers utilize PowerView to automate enumeration and discovery of GPOs.
PowerView scripts can quickly enumerate policies, permissions, and configurations, significantly reducing reconnaissance time and effort.
Ryuk Ransomware Attacks:
Attackers behind Ryuk ransomware have been observed enumerating Group Policies to identify security settings and disable antivirus or endpoint protection via compromised GPOs.
This enabled rapid lateral movement and widespread ransomware deployment across victim networks.
These examples highlight the critical importance of detecting and mitigating Group Policy Discovery, as adversaries frequently leverage this technique to facilitate advanced and impactful attacks.