Active Directory Security Best Practises

When Active Directory manages a large IT infrastructure and userbase naturally security risks arise, especially when Active Directory is not setup or managed according to best security practices. For this reason, attackers find Active Directory a lucrative target to attack victim organizations. 

There are many security issues that could weaken Active Directory deployments and make them vulnerable. In this blog, we will highlight a number of the most prevalent security issues we have identified during our security projects, and what proactive measures you can apply to prevent or limit related security risks. 

Common Active Directory Security Issues

Here are the common security issues that usually affect Active Directory deployments when the IT environment gets complicated and cyber hygiene is not well practiced: 

Weak and guessable account passwords 

Weak passwords present a significant security risk. Attackers will usually attempt to perform password spraying on services that utilize Active Directory for authentication. Once successful, it is an easy entry point to the organization’s Active Directory environment. 

Overly permissive users and groups 

It may seem an easy approach for system admins to just grant users excess privileges such as local admin or Domain Admin privileges to avoid troubleshooting access issues and errors with integrated applications. While it makes things work with less effort, it also gives attackers (or malware) who’s able to compromise the account high permissions that can be used to further their steps within the environment.  

Forgotten and unused active user accounts 

This is a common issue for accounts for resigned employees and contractor’s accounts whose projects have completed. Their accounts stay active and forgotten by Active Directory admins. This gives attackers a higher probability of account compromise and take over. 

Inadequate protection for privileged accounts 

Highly privileged accounts, such as local administrators, Domain Admins, and others are more attractive to attackers than normal domain user accounts since they already have the privileges the attackers need to perform their nefarious activities. 

Vulnerable and outdated domain controllers 

Domain controllers are the brain that runs Active Directory and store users accounts and their password hashes. When domain controllers are vulnerable due to a lack of patching for instance or misconfiguration, attackers can directly exploit them and access credentials and compromise accounts.  

Insufficient security monitoring 

The lack of logging and sufficient security monitoring to spot malicious activities revolving around Active Directory services can lead admins to miss early signs of malicious activities or compromises which could be prevented to avoid severe damages. With the lack of security monitoring, attackers might be already wandering unnoticed around the Active Directory environment. 

Using the same credentials on different systems 

When the same local administrative account credentials of a compromised Microsoft Windows host is used on other Windows hosts, attackers can reuse these account password hashes to access other systems using techniques such as Pass-the-Hash (PtH). This is somewhat equivalent to having a Domain Admin access since attackers can access any host in the environment. 

Active Directory Security Measures

Investing in secure architecture and configuration will cost way less than recovering from a security incident if full recovery is even possible. There are different measures you can apply to elevate the security posture of your organization’s Active Directory and manage the security risks mentioned above. Here are the top recommended measures for secure Active Directory deployment: 

Enforce a strong password policy 

It’s a simple and not costly measure yet very effective to avoid security compromises. You can be wishful that users will create strong passwords especially when they are given awareness about the risk of using weak passwords and their security consequences. However, it is safer and more effective to implement and enforce technical controls that will prevent users from creating weak and guessable passwords. 

Grant permissions based on need-to-know principle 

While it takes more effort and time for system administrators to tailor and maintain custom permissions for users and application accounts, it is an effort worth spending to grant these permissions based on functional requirements without having excess privileges vulnerable to abuse for escalation in case of a security compromise.    

Disable stale and unused user accounts 

It is important to have a strict process in place to disable those accounts which are not anymore required. For instance, when employees have left the company, or a project has been signed off. The process should involve performing regular audits for the Active Directory accounts to ensure no unused account is active. Stale accounts can be identified from the last time they logged in. If you find an account that has not been used for over two months, for instance, it should raise a flag why it is still active.  

Pay special attention to privileged accounts protection 

Additional security measures should be applied to privileged accounts, like Domain Admins, Enterprise Admins, and other service accounts with high privileges. In addition to strict password policies, enable multi-factor authentication, and apply restrictions from where these accounts can connect and login. 

Regularly update and patch domain controllers 

Domain controllers are critical IT assets and must be patched as soon as a security update is released. Patches should of course be evaluated and tested before being rolled out to production instances to avoid technical issues caused by security updates.  

Monitor unauthorized access events and other security threats 

Preventive security measures alone can’t stop security attacks as attackers will eventually find their way through vulnerable or misconfigured systems and networks. This is why it is important to implement proper security monitoring measures that proactively keep system administrators aware of ongoing suspicious events toward their infrastructure and stop these malicious attempts before a security breach occurs.  

Randomize local admin passwords on every system 

Windows Local Administrator Password Solution (LAPS) can be utilized to prevent attackers from pivoting to other systems in case one Windows host has been compromised. There are other solutions that will also randomize the local administrator password on every machine to make it impossible to reuse the password hash of a compromised account to break into other systems. 

Perform regular security and health checks for Active Directory 

You can’t mitigate risks before they are identified. That’s why it’s important to continuously assess and audit your Active Directory environment. This is the way you can identify any unknown vulnerabilities and security risks and mitigate them. Since the Active Directory environment is constantly evolving and changing as the organization grows, it’s important to perform those assessments on a regular basis to identify vulnerabilities that may arise between assessment cycles. 

Want Help With Securing Active Directory?

Oivan experts have an extensive experience in designing, implementing, managing, and auditing Active Directory. If you are interested to know more about how we can help you with your Active Directory security, send us a message and we will be in touch: