How to Secure Active Directory?

How to Secure Active Directory

Active Directory is more than a directory service; it’s the hub of your IT infrastructure, making its security an absolute top priority.

Unauthorized access to your AD can lead to costly financial losses and brand tarnishing for your organization, so to prevent such disasters you must protect privileged access.

Access Control

As an organization expands, more devices must be added to its network. To maintain a safe environment, it’s crucial that organizations regularly audit and monitor all new devices being added into their domain in order to detect any irregular or illegal devices as this helps detect security incidents or policy violations before they become serious issues that require urgent resolution.

Active Directory breaches can be devastating for organizations. Compromise of stolen credentials could allow attackers to gain entry to users, databases and applications connected to it; those with extensive privileges could subsequently move laterally through your system and steal more data or create backdoor accounts that allow further attacks to come from within your own system. As per Verizon’s 2021 Cost of Data Breach Investigation Report, any breach resulting from compromised AD credentials often takes weeks or even months for organizations to discover.

Attacks against Active Directory can come from unpatched applications, OS, and firmware vulnerabilities on domain controllers or from brute force password attacks. A well-configured Active Directory should implement strong password policies requiring minimum length, complexity requirements and account lockout after certain failed attempts to deter brute force attacks; additionally it should use Role Based Access Control to limit permissions based on users’ job roles.

Erase any outdated protocols like Server Message Block v1 (SMBv1), Digest Authentication and LAN Manager/NTLMv1 and v2, which are vulnerable to man-in-the-middle attacks and replace them with Kerberos, a more secure protocol designed with current threats in mind.

Implement a Windows audit trail that monitors server activity in real-time and reports back on it, giving administrators visibility into any login attempts that appear suspicious or may signal an attack, such as those coming from unknown IP addresses, repeated login failures from one user, or multiple failed login attempts from multiple accounts. With this information at their disposal, alerts can quickly be set off that can help stop breaches in progress.


Active Directory auditing is the practice of tracking changes and actions performed on AD objects to detect security threats, with the objective being to detect activity that could negatively impact an organization, fall outside normal security parameters or violate established policies. To quickly and effectively detect threats it’s essential that clear definitions exist regarding what activities should be monitored. This allows IT pros to focus on significant events while reducing alert fatigue caused by monitoring too many potential activities across all aspects of IT ecosystem.

Though Active Directory’s default audit settings are robust, it’s still wise to refine them to ensure that only critical security events are logged. For instance, devices joining domains often don’t log enough information about system events like user account lockouts and password resets unless audit settings have been optimized to do so.

Implementing clear metrics and criteria to assess the effectiveness of security controls is also highly recommended, helping IT teams objectively assess their current state and identify areas where improvements need to be made.

As an indicator of brute-force attacks, an unexpected increase in account lockouts can be a sure sign. Dormant accounts can give attackers access to your network and enable them to steal important data. To protect yourself against this risk, it’s essential that strict password policies and monitoring changes to account permissions be put in place and adhered to.

Unother key element in ensuring adequate security measures are in place is through adopting best practices like change management and privileged access management (PAM). Change management ensures any alterations made to objects within Active Directory follow a formal, documented procedure; this reduces risks associated with unapproved changes while decreasing configuration errors. PAM refers to practices designed to control, monitor and secure all human and non-human privileged access in your IT ecosystem – such as passwords, administrative privileges and sensitive resources.

Patch Management

Active Directory, as an integral component of IT infrastructure, must be safeguarded against attack. Attackers may exploit weaknesses that compromise this environment to gain entry and attack other parts of your network – however there are tools available to you that can protect AD from attacks.

Patch management software automates the process of scanning and deploying patches across endpoints, with some solutions offering features to test patches and software updates before authorizing enterprise wide deployment – helping ensure that only relevant patches reach specific machines.

Limiting access to sensitive applications and data is another essential element of patch management. By default, AD has three built-in groups with full, privileged access: Enterprise Admins, Domain Admins and Administrators; it is essential that this privilege only be granted to individuals who need them for their jobs – and restrict any systems such as domain controllers or administrative hosts with privileges as much as possible.

Finally, it is of utmost importance that software and hardware remain updated with patches and updates, reducing your attack surface while increasing security, usability, and performance. Lax patch management can open your network up to attacks; even one vulnerable computer could lead to larger breaches if left vulnerable.

By implementing multiple of these tools, you can greatly strengthen the Active Directory security. However, remember that deploying one tool alone won’t close all gaps; they must be combined with projects and processes carried out as part of Active Directory security projects, including:

Password Policy

Passwords are the main way of accessing AD and its resources, making strong password policies an essential element of security. Passwords that are easy to guess or crack can provide attackers with a pathway into your domain; by enforcing a stringent policy requiring passwords with letters, numbers, and special characters as part of an overall password strategy you can help secure privileged user accounts while regularly changing them further enhances this form of protection.

Cracked passwords allow hackers to gain entry to privileged accounts and spread malicious infections throughout a domain. To avoid this happening, securing domain administrator accounts with strong passwords that are difficult for hackers to break or guess is the best way. Furthermore, adopt a least privilege approach when giving domain admin rights to users so as to only provide them with what is necessary.

Active Directory domains allow administrators to configure six password policy settings. One is “Enforce Password History,” which determines how many previous passwords will be remembered by each user account – Microsoft recommends 24 remembered; critics of this setting, however, argue it is too lax, since users could simply shift through previous passwords by incrementing one character at a time.

Other password policies to consider are Minimum Password Length and Complexity. In general, for general users with 8 character password length requirements and complexity difficult for hackers to brute force attack or dictionary search should suffice. This will protect them against accidental lockout due to typos or writing down their password in an insecure place.

Configuring password policies within the Default Domain Policy or creating a new Group Policy object (GPO). Once created, PSOs can be linked with users and global groups either during creation or later through GPO Manager, providing password requirements and lockout settings according to your design. You can name them, set precedence values and name them accordingly.

Mark Funk
Mark Funk is an experienced information security specialist who works with enterprises to mature and improve their enterprise security programs. Previously, he worked as a security news reporter.