Checking Active Directory (AD) for vulnerabilities involves a combination of manual checks, automated tools, and best practices to identify misconfigurations, weak security settings, and potential attack vectors.
Below are steps and methods to assess AD for vulnerabilities, keeping the answer concise yet comprehensive:
1. Manual Configuration Review
• Check Group Policy Settings: Review Group Policy Objects (GPOs) for insecure settings, such as weak password policies (e.g., short password lengths, no complexity requirements, or long password age). Use the Group Policy Management Console (gpmc.msc) to audit settings.
• Examine User and Admin Accounts:
• Identify accounts with excessive privileges (e.g., Domain Admins, Enterprise Admins).
• Check for stale or unused accounts with high privileges using PowerShell:
Get-ADUser -Filter {Enabled -eq $true} -Properties LastLogonDate | Where-Object { $_.LastLogonDate -lt (Get-Date).AddDays(-90) }
• Ensure accounts don’t have “Password Never Expires” enabled unnecessarily.
• Review Trusts: Verify domain and forest trust relationships for unnecessary or overly permissive trusts using nltest /domain_trusts.
• Check Kerberos Configurations: Look for weak encryption types (e.g., DES, RC4) in Kerberos authentication. Use Get-ADObject to inspect Kerberos settings.
• Audit Permissions: Check for overly permissive access control lists (ACLs) on AD objects (e.g., users with GenericAll permissions). Use tools like dsacls or PowerShell’s Get-Acl.
2. Use Automated Tools for Vulnerability Scanning
• PingCastle: A free tool to audit AD security. It generates reports on misconfigurations, weak passwords, and privilege escalation risks. Run it with admin credentials for a full scan:
pingcastle.exe --healthcheck
• BloodHound: Identifies attack paths in AD, such as excessive permissions or misconfigured trusts. Import data with SharpHound and analyze in BloodHound GUI to visualize paths to Domain Admin.
• Microsoft Defender for Identity: A cloud-based solution that monitors AD for suspicious activities and vulnerabilities, such as weak protocols or anomalous logins.
• PowerSploit/PowerView: PowerShell scripts to enumerate AD for misconfigurations (e.g., Find-DomainUserLocation to locate privileged users).
• Purple Knight: A free tool by Semperis that scans AD for vulnerabilities and provides a security score with remediation steps.
3. Network and Protocol Analysis
• Check for Weak Protocols: Ensure legacy protocols like NTLMv1, SMBv1, or LDAP signing disabled are not in use. Use Get-ADDomain to verify settings:
Get-ADDomain | Select-Object NetlogonAllowNTLM
• Monitor LDAP Traffic: Ensure LDAP is secured with LDAPS (port 636) and check for unencrypted traffic using tools like Wireshark.
• Kerberos Attacks: Test for Kerberos vulnerabilities like Kerberoasting by attempting to extract service account hashes:
Invoke-Kerberoast -OutputFormat Hashcat | Export-Csv kerberoast.csv
4. Patch and Update Management
• Ensure domain controllers are fully patched to mitigate known exploits (e.g., ZeroLogon, PrintNightmare). Use Get-WindowsUpdate or WSUS to verify patch status.
• Check for outdated operating systems (e.g., Windows Server 2008) that no longer receive security updates.
5. Penetration Testing
• Conduct controlled tests to simulate attacks like:
• Pass-the-Hash: Test if stolen NTLM hashes can be used to move laterally.
• Golden Ticket Attacks: Verify if Kerberos TGTs can be forged due to weak KRBTGT passwords.
• Use tools like Mimikatz or CrackMapExec for ethical testing in a controlled environment.
6. Log and Event Monitoring
• Enable and review Security Event Logs on domain controllers for suspicious activities (e.g., Event ID 4624 for logons, 4672 for privilege assignments).
• Use tools like Event Log Analyzer or Splunk to detect anomalies, such as mass account lockouts or brute-force attempts.
7. Best Practices to Mitigate Vulnerabilities
• Enforce strong password policies and enable multi-factor authentication (MFA) for privileged accounts.
• Limit Domain Admin usage and implement Privileged Access Management (PAM).
• Regularly rotate KRBTGT account passwords:
Reset-ADServiceAccountPassword -Identity KRBTGT
• Restrict RDP access to domain controllers and use network segmentation.
8. External Resources
• Microsoft Best Practices Analyzer: Run the BPA for Active Directory to identify compliance issues.
• CIS Benchmarks: Follow the Center for Internet Security’s AD hardening guidelines.
• MITRE ATT&CK Framework: Map AD vulnerabilities to ATT&CK techniques (e.g., T1078 for valid accounts).
Notes
• Always perform tests in a controlled environment with proper authorization to avoid disrupting production systems.
• If you need real-time data or analysis of specific AD configurations, provide details, and I can guide you further or search for relevant tools/posts.