As cyber threats continue to be more sophisticated, the need for active directory security becomes paramount. Most Windows-based environments are heavily reliant on the AD configuration hence it’s a common target for intruders. Without proper directory hardening, the active directory domain becomes a major attack vector for threat actors seeking to compromise sensitive data or disrupt operations. Attackers often attempt to compromise Active Directory to gain unauthorized access and establish control over enterprise networks. This article outlines essential practices for AD hardening to protect your organization’s assets and reduce the risk of breaches.
Best Guide to Hardening Your Active Directory
User authentication and access control are significantly dependent on Active Directory, and this makes it a desirable target for attacks. Therefore, to enhance AD security and reduce vulnerability, adopt a multi-layered approach.
Before moving forward, let’s briefly explore the various threats that could be aiming for your Active Directory.
Common Active Directory Attacks and How to Mitigate them:
- Credential Theft: Attackers use phishing attacks to get hold of the credentials and then use it to their benefit. The best approach to defend yourself against it is to implement multi-factor authentication (MFA).
- Pass-the-Hash Attacks: Here malicious actors steal a “hashed” user credential and then they create a new session on the same network. To stand strong against such attacks you need to make sure that your systems are regularly updated, you limit network access, and implement an Identity Threat Detection and Response (ITDR) solution.
- Brute-Force Attacks: This attack is commonly used to bypass your security system and get access to accounts by attempting different patterns for the passwords. In this case, you can implement robust password policies to enhance security. Account lockout policies can help prevent brute-force attacks by temporarily locking accounts after multiple failed login attempts, making it harder for attackers to guess passwords.
- Insider Threats: To avoid insider attacks, you can limit user permissions. Regularly review permissions for domain users and user accounts to prevent excessive privileges. It is also important to audit administrative accounts and domain administrator privileges to reduce the risk of insider threats, as these accounts have elevated access.
- Advanced Strategies
- Multi-layered Defense
- Security Checklist
Using group policy objects, you can enforce security settings across all domain users and user accounts, ensuring consistency.
Security monitoring is essential for detecting security incidents in Active Directory. Monitoring should also extend to other systems beyond Active Directory to provide comprehensive threat detection and response.
Now that you are familiar with the attacks, let’s have a look at the Active Directory hardening best practices to make the environment as safe as possible.
Active Directory Best Practices for Hardening
1. Strengthen Access Controls
Password Policies: Enforce strong password policies with at least 15 characters, uppercase letters, lowercase letters, numbers, and symbols.
Multi-Step Authentication: Users should be made to use MFA for an added layer of protection.
Least Privilege Principle: Users should be given access rights only needed for their jobs to lower the impact compromised accounts have on the system. Regularly review permissions for user objects and user and computer objects to ensure no excessive privileges are granted. Restrict access for service accounts and ensure they have only the permissions necessary for their function. Limit the use of local administrator and built in administrator account privileges to reduce risk.
2. Protect Domain Controllers
Security Patches: Timely update your domain controllers to avoid vulnerabilities that have already been discovered.
Network Segmentation: Isolate the affected domain controllers, preventing lateral movements in networks.
Privileged Access Workstations: It is advisable to use specific computers for administrative duties to minimize contamination with viruses. Restrict who can access domain controllers and monitor access domain controllers for unusual activity. Ensure that computer objects representing domain controllers are properly configured for security, and that all computers configured for administrative access follow best practices. Additionally, disable or secure the print spooler service on domain controllers to prevent exploitation.
3. Enhance Monitoring and Response
Activity Monitoring: Continuous monitoring helps in detecting any suspicious activity at an early stage. Enable advanced audit policy to capture detailed security events, such as account logins and policy changes. Monitor for suspicious activity related to kerberos service tickets and the ticket granting service to detect potential attacks like Kerberoasting.
Vulnerability Assessments: Regular assessments should be done to detect and patch security gaps.
Threat Detection Solutions: Implement SIEM tools for real-time monitoring as well as immediate action in case something goes wrong. Rapid response to security incidents is crucial to minimize damage and prevent escalation.
4. Implement Read-Only Domain Controllers
Read-only domain controllers (RODCs) offer a secure solution for extending Active Directory services to remote or branch office locations. Unlike traditional domain controllers, RODCs hold a read-only copy of the Active Directory database, allowing them to authenticate users locally without exposing the entire domain to unnecessary risk. By deploying RODCs, organizations can limit the exposure of sensitive data and reduce the attack surface in environments where physical security or network connectivity may be less reliable.
This approach strengthens the overall security posture of the active directory environment, ensuring that even if a remote site is compromised, the impact on the core domain remains minimal.
5. Use Group Managed Service Accounts
Group managed service accounts (gMSAs) are designed to provide a secure and efficient way to manage service accounts within the active directory environment. Unlike traditional service accounts, gMSAs are automatically managed by the active directory domain, eliminating the need for manual password management and reducing the risk of credential theft.
By implementing group managed service accounts, organizations can ensure that services are authenticated securely, credentials are rotated automatically, and the risk of compromise is minimized. This not only enhances the security posture of the active directory environment but also simplifies the management of service accounts across multiple servers and applications.
6. Secure LDAP Communication
The Lightweight Directory Access Protocol (LDAP) is a critical component for communication between applications and the Active Directory database. Securing LDAP communication is essential to protect sensitive data from unauthorized access and interception.
By enabling LDAP signing and encryption, organizations can ensure that data transmitted between clients and domain controllers is protected against eavesdropping and tampering. Securing LDAP communication is a fundamental step in safeguarding the integrity of the active directory environment and preventing attackers from exploiting unencrypted channels to gain access to sensitive information.
7. Reduce the Attack Surface
Reducing the attack surface is a cornerstone of hardening the active directory environment. This involves implementing layered security measures such as network segmentation to isolate critical systems, enforcing strict access controls, and applying the principle of least privilege to limit user and service permissions.
Multi factor authentication adds an extra layer of protection against unauthorized access, while continuous monitoring helps detect and respond to suspicious activity before it escalates into a security incident. By proactively managing privileges, segmenting the network, and monitoring for threats, organizations can significantly decrease the likelihood of compromise and protect sensitive data within their active directory environment.
Active Directory Hardening Checklist
1. Access Control
- Implement strong password policies
- Enforce MFA
- Review permissions for user accounts and domain users to ensure there are no excessive privileges.
- Modify permission if needed
2. Domain Controller Security
- Make sure domain controllers are up to date
- And all the patches are implemented
- Verify that computer objects representing domain controllers are properly configured for security, and ensure the print spooler service is disabled or secured on these computers configured to prevent exploitation through unconstrained delegation
3. Monitoring and Assessment
- Analyze security logs
- Use automated tools to zero in on potential vulnerabilities
- Ensure advanced audit policy is enabled for detailed event logging, and that security monitoring is in place to detect and respond to security incidents
- Top Active Directory threats
- Learn how attackers gain access and how to prevent it
- Proactive strategies to strengthen your defenses
Conclusion
Securing your Active Directory is not a one-time thing, it’s an ongoing process. By implementing these Active Directory best practices, you can build a strong defense for your AD environment against ever evolving cyber threats. For a deeper and detailed understanding get your hands on our white paper and connect with experts.
By adopting these strategies, you ensure that your Active Directory remains resilient against evolving cyber threats, safeguarding your organization’s most valuable assets.
