Active Directory (AD) is a critical component of many IT infrastructures, as it provides authentication and authorization services for users, computers, and applications. However, AD also poses significant security risks if not properly configured and protected. Here are the security best practices for securing Active Directory in any organization.
1. Review and Amend Default Security Settings
AD comes with default security settings that may not suit your organization's needs or comply with your security policies. For example, the default password policy may be too weak, the default domain controllers policy may grant excessive privileges to certain groups, or the default audit policy may not capture enough events for monitoring and investigation. Therefore, it is important to review and amend the default security settings to align them with your security requirements and best practices.
2. Implement Principles of Least Privilege in AD Roles and Groups
One of the key principles of security is to grant users and administrators only the minimum level of access they need to perform their tasks. This reduces the attack surface and limits the potential damage in case of compromise. In AD, this means that you should avoid adding users to privileged groups such as Domain Admins, Enterprise Admins, Schema Admins, or Administrators, unless absolutely necessary. Instead, you should create custom groups with specific permissions and delegate them to the appropriate users or organizational units (OUs). You should also regularly review the membership of privileged groups and remove any unnecessary or inactive accounts.
3. Control AD Administration Privileges and Limit Domain User Accounts
Another way to implement least privilege is to control AD administration privileges and limit domain user accounts. This means that you should use separate accounts for administrative tasks and normal tasks, and avoid logging in with domain administrator accounts on regular workstations or servers. You should also use secure admin workstations (SAWs) or jump servers for performing administrative tasks on domain controllers or other sensitive systems. Additionally, you should limit the number of domain user accounts that have local administrator privileges on workstations or servers, as they can be used to escalate privileges or move laterally within the network.
4. Use Real-Time Windows Auditing and Alerting
Auditing and alerting are essential for detecting and responding to malicious activities or anomalies in AD. You should enable audit policy settings with group policy to capture events such as logon/logoff, account management, object access, policy change, privilege use, system events, etc. You should also use a centralized logging solution to collect, store, analyze, and alert on these events in real-time. This will help you identify suspicious or unauthorized actions such as password changes, group membership changes, privilege escalation attempts, credential theft attempts, etc.
5. Ensure Active Directory Backup and Recovery
Backup and recovery are vital for ensuring the availability and integrity of AD in case of disaster or compromise. You should have a backup strategy that covers all domain controllers and other critical AD components such as DNS servers, global catalog servers, FSMO role holders, etc. You should also test your backups regularly and ensure that they are encrypted and stored securely. Moreover, you should have a recovery plan that outlines the steps and procedures for restoring AD from backup in different scenarios such as hardware failure, data corruption, ransomware attack, etc.
6. Patch All Vulnerabilities Regularly
Patching is one of the most effective ways of preventing attacks and reducing vulnerabilities in AD. You should apply security updates and patches to all domain controllers and other AD-related systems as soon as they are available from Microsoft or other vendors. You should also use a vulnerability scanning tool to identify any missing patches or misconfigurations in your AD environment and remediate them promptly.
7. Centralize and Automate Security Management and Reporting
Managing security for a large and complex AD environment can be challenging and time-consuming. Therefore, it is advisable to use a centralized and automated solution that can help you with security management and reporting tasks such as:
- Monitoring AD health and performance
- Enforcing security policies and compliance standards
- Detecting and alerting on security threats or incidents
- Investigating and resolving security issues
- Generating security reports and dashboards
Such a solution can help you save time and resources, improve visibility and accountability, and enhance security posture and resilience.
