What is Active Directory Security?

Active Directory is a directory service offered by Microsoft Windows that helps administrators configure permissions and network access. Microsoft Windows Active Directory has several components, including Active Directory Domain Services, Active Directory Certificate Services and Active Directory Federation Services.

Information technology (IT) administrators rely on these Microsoft Active Directory services to perform a variety of daily processes, including domain controller workflows. For example, when a user logs on to a domain joined device, the domain controllers authenticate the user name and password. If the user is a system administrator, domain controllers can grant additional permissions.

Microsoft Active Directory security is important for businesses because the service holds the keys to the kingdom — providing access to systems, applications and resources. Businesses must be aware of vulnerabilities and take steps to strengthen their Active Directory security, like using security tools or following best practices, to keep their networks safe from cyberattacks.

Reasons Active Directory Security Is Critical

The main factor that makes Active Directory security, or AD security, uniquely important in a business’s overall security posture is that the organization’s Active Directory controls all system access. Effective Active Directory management helps protect your business’s credentials, applications and confidential data from unauthorized access. It’s important to have strong security to prevent malicious users from breaching your network and causing damage.

Risks of Neglecting AD Security

If you neglect Active Directory security, you’re at risk for the following kinds of cyberattacks and escalations:

• Initially, malicious users can steal credentials or gain access using malware and then monitor your activity.
• Malicious users can then infiltrate additional accounts and move laterally through your system.
• With extensive access to your network, malicious users can either steal data or corrupt your system.

Challenges for AD Security Recovery

The biggest challenges for recovery after an Active Directory security breach are identifying the breach source, determining the extent of the damage and creating a safe new environment. According to Verizon’s 2021 Data Breach Investigations Report, 98% of data breaches came from external agents and 85% of data breaches took weeks or longer to discover.

Malicious users often gain access to a user account and remain undetected before compromising more of the system. The longer a hacker remains undetected in your system, the more damage they can inflict. Additionally, it can be challenging to trace all the areas that they have breached. As a result,  attempting to patch vulnerabilities in an existing system might be ineffective. Organizations with complex or older infrastructure could benefit instead from porting the most important user accounts and information to a new and smaller system that they can keep secure.

Because of the importance of Active Directory security, organizations should make disaster recovery plans so they are prepared to act quickly in the event of an Active Directory attack. By vigilantly monitoring for unauthorized access and having a plan, organizations have the best chance of stopping an attack before the system is corrupted or becomes irreparable.

Vulnerabilities in Active Directory

The best way to monitor for compromises in your Active Directory is to use an event log monitoring system. According to Verizon’s 2021 Data Breach Investigations report, 84% of organizations that had a breach had evidence of the breach in their event logs. By monitoring the activity in these logs, organizations can catch any compromises before more damage occurs.

When monitoring your event logs, look for signs of suspicious activity, including the following events:

• Privileged account activity: Attackers commonly exploit a privilege vulnerability and attempt privilege escalation, increasing the privileges of a compromised user account. Alternatively, you might notice after-hours activity on a privileged user account or a sudden increase in the amount of data accessed by the user account.
• Login failures: Repeated failures to log in to an account can be a sign that a threat actor is trying to gain access.
• Remote logins: Malicious users often attempt to access your system remotely. If you notice a login from an Internet Protocol (IP) address in a different country or locale, it could be a sign that your Active Directory is compromised.

Just like there can be many different signs of an Active Directory compromise, there are many types of vulnerabilities. Let’s take a look at some of the most common vulnerabilities that malicious users can exploit.

All Users Have Rights to Add Workstations to the Domain

By default, any domain user can add workstations to the domain. The risk of this configuration is that users can join personal computers to access your corporate domain too. Personal computers might not have protection from your antivirus or endpoint detection and response software. Your organization’s settings and policies might not apply on the added workstations. This Active Directory configuration also allows users to have local administrative privileges on their machines. Local administrative privileges on personal machines pose a security risk because users can perform actions that could attack other systems on the network.

To limit this vulnerability, adjust the ms-DS-MachineAccountQuota attribute to limit the ability to add computers to your domain. You can delegate permissions for creating computer accounts to specific users or a group of users that you specify instead.

Too Many Users in Privileged Active Directory Groups

The risk of a domain compromise increases when you increase the number of users in a privileged security group like an Active Directory group of domain administrators or enterprise administrators. A domain administrator, or domain admin, has full control of the domain. A domain admin is typically a member of the administrators group on all domain controllers, all domain workstations and all domain member servers. Because these user accounts have extensive security privileges, your domain could become compromised if a threat actor steals the credentials of the users in these security groups.

To limit this vulnerability, review privileged access management and group policy management settings and policies regularly. Make sure that users have only the permissions necessary to perform their jobs. Add users to these privileged security groups only when it is essential so that the groups don’t grow too large.

Weak Password Policy

There are different philosophies on how to best balance password security with convenience. If an organization requires users to create complex passwords and change them frequently, users might forget their passwords and store them in an insecure way. If an organization allows less complex passwords, hackers might more easily gain access to the system.

To limit this vulnerability, organizations should set a conservative password policy and ensure there are other security controls in place in case a password is compromised. For example, if your access rights manager needs to trigger a password reset for an Active Directory user, there should also be security controls to verify the user’s identity.

Best Tools for Active Directory Security

You can use security tools to protect Active Directory security and perform Active Directory monitoring of the health of your system. The main benefits of using Active Directory security tools are convenience, automation and enhanced security. Many Active Directory tools provide a more usable interface for performing administrative tasks, can automate tasks like cleaning up abandoned accounts and help strengthen security through monitoring and alerts.

Active Directory is a large service with many applications, so Active Directory tools vary in purpose and scope. The tools available range from free programs that monitor for basic signs of a breach to robust services that provide comprehensive threat detection and prevention. To compare the benefits of the available Active Directory tools, you should first decide your budget and then consider the features that are more important to your organization. Consider the most time consuming or most risky processes at your organization and look for a tool that addresses those needs.

When choosing an Active Directory security tool that is right for your organization, consider looking for a tool that has some of the following features:

• Automation for creating user accounts and security groups
• Analysis of user permissions
• Analysis of vulnerabilities, such as abandoned accounts
• Active Directory auditing for changes to parameters
• Free trials to test how the tool works for your organization

You can also take a technical risk assessment that identifies vulnerabilities and weak settings that inhibit having a clean Active Directory. Based on your results, you can determine which security areas need the most support and identify the tools that can help.

Keep in mind that comprehensive threat detection tools could be more cost effective for your business if they allow you to reallocate resources to other tasks. Threat detection tools can automatically monitor for suspicious activity and reduce the amount of time it takes to resolve incidents. When the tool does the heavy lifting, your staff can focus on other tasks that bring value to your business.

Active Directory Security Best Practices

Many malicious users breach your system using compromised credentials. As a result, it’s important to follow Active Directory best practices to avoid unnecessary security risks. The best ways of hardening your Active Directory are to implement the following security measures:

• Adjust default security settings to fit your organization’s needs.
• Use backup and recovery processes.
• Centralize security management and reporting.

1. Adjust Default Security Settings

Some default Active Directory settings, like the setting allowing all users to add workstations to your domain, give unnecessary privileges to users at your organization. When you install Active Directory, review the security configuration and make changes to fit your organization’s needs. You should also review all user permissions to ensure you’re granting only the minimum level of access needed.

By limiting permissions, malicious users are less likely to gain privileged access, and employees at your organization are less likely to abuse privileges. To adjust default security settings, you can manually change attribute values and permissions or use Active Directory tools that help you configure these settings.

2. Use Backup and Recovery Processes

The most important backup measure for securing Active Directory is making sure you back up your Active Directory regularly and at least every 60 days. The lifetime of Active Directory tombstone objects is 60 days. You can prevent errors about expired tombstone objects by having an Active Directory backup that is less than 60 days old. It’s also a best practice to have more than one backup stored in different locations in case a backup is also compromised.

The most important recovery measure for securing Active Directory is outlining a disaster recovery process. This process should indicate the steps your security team needs to take when recovering from a breach. You need to consider the recovery sequence and dependencies because a domain controller, for example, needs to be recovered before you can recover other machines.

3. Centralize Security Management and Reporting

By centralizing security management and reporting, organizations have a dedicated team that is responsible for Active Directory security. These employees can gain expertise and respond quickly to an attack. A comprehensive threat detection tool can also help your security team review and monitor the system using one program that allows them to investigate alerts quickly.

Threat Detection Using CrowdStrike

Strengthening your Active Directory security is important to protect your business from cyberattacks. Because the tactics and tools of malicious users change over time, IT teams must stay informed about the latest threats and continuously monitor for any signs of a breach.

CrowdStrike Falcon® Identity Threat Detection can help you detect identity-based threats in real time using artificial intelligence and behavioral analytics to stop modern attacks like ransomware. By using this threat detection tool, IT teams can fully understand their network accounts, identify suspicious activity and respond quickly to threats. CrowdStrike offers a free trial so you can see how the cloud security service would work for you.