Active Directory Disaster Recovery Steps and Best Practices

Steps for Active Directory Disaster Recovery

When Active Directory fails, the entire organization loses its ability to operate effectively as it is responsible for providing essential services that employees need to access data, run applications, and serve customers. The cost of downtime can be immense, with some enterprises reporting losses of millions of dollars per minute. The recovery process involves restoring the domain controllers, syncing them with replication partners, and making them available again. It is recommended to approach AD disaster recovery in phases, starting with restoring one key domain controller to quickly to get the organization running again and then promoting the remaining domain controllers using “install from media” for a faster process. Below are some of the key steps you should take to improve AD disaster recovery, which can be performed before, during and after, disaster strikes:

Step 1: Determine if forest restoration is required

In the event of Active Directory failure, you will need to determine if forest restoration is necessary. Some examples of widespread forest failures that may warrant restoration include a logical corruption or physical damage to all domain controllers, which would make business continuity impossible as applications reliant on AD DS would not function. Another situation that could arise is the deliberate or accidental execution of a script by an attacker or administrator, causing data corruption throughout the forest. Additionally, deliberate or accidental changes to the AD schema, or the installation of malicious software on domain controllers by an attacker, may also warrant restoration. Other circumstances include the complete failure of replication between domain controllers, the inability to make any modifications to AD DS at any domain controller, or the inability to install new domain controllers on any domain. If forest recovery is required, you will need to assess the existing forest structure, ascertain the roles performed by each DC, select the appropriate DC to restore for each domain, and make sure to deactivate all writeable DCs.

Step 2: Ensure that you have a secure backup of AD

It is important to regularly back up your Active Directory and store the backups in a secure location. Microsoft recommends following the 3-2-1 rule, which involves keeping three backups on two different storage types and storing at least one backup offsite and offline. Different types of backups include System State backups, which contain the entire operating system, and Bare Metal Recovery (BMR) backups, which allow for restoration to different hardware instances. Third-party solutions offer additional backup options specifically for AD and Azure AD. VM snapshots are not suitable for AD backups as they can cause data consistency issues and may include malware. Additionally, you must ensure that VM snapshots are properly protected during disaster recovery.

Step 3: Establish emergency communication protocols

To ensure effective communication during downtime of Active Directory, it is important not to rely on potentially unavailable IT systems like email or Microsoft Teams. It’s a good idea to use a secure messaging solution that works across different platforms and perhaps even share the mobile phone numbers of your recovery team members to send notifications. It is also essential to store the AD disaster recovery plan somewhere accessible in case of AD failure. Options include printing it out or storing it in a separate cloud storage container.

Step 4: Identify the key decision-makers

Establish individuals or teams who will be responsible for decision-making at each critical point and ensure their accessibility at any given moment. Keep in mind that in the event of a system failure, time is of the essence. Therefore, during the restoration process, it is essential to have a clear understanding of who is empowered to initiate recovery and who is accountable for specific tasks.

Step 5: Document your Disaster Recovery Plan (DRP)

An Active Directory Disaster Recovery Plan (DRP) can be a lifesaver during a disaster. It is beneficial to have an easy-to-follow guide with pictures, designed for beginners. This is because during a disaster, when stress levels are high, it may be difficult to think clearly. The plan should include gathering detailed information about the forest and domains, documenting backups and passwords, developing a communication plan, and creating a plan for forest recovery. It also outlines the process for recovering SYSVOL data, recovering objects in Active Directory, recovering DNS, and documenting known errors discovered during firedrills. Additionally, you should compile a list of commands and tools used during firedrills and create an ISO image with necessary tools for the recovery process.

Step 6: Test your recovery plan

It is crucial to identify and correct any missing information in your disaster recovery plan. Continuously test and revise the plan until it is strong and can be executed by any qualified IT team member. It is vital to have individuals who did not create the plan carry out testing as they bring a valuable fresh perspective. However, troubleshooting issues with AD is too complicated for a non-expert, and so testers should be AD architects who possess a solid understanding of your organization’s AD deployment. To accelerate AD disaster recovery, it is crucial to repeatedly rehearse the protocols outlined in your plan until they are second nature. Every team member must possess thorough knowledge of their respective duties for various recovery situations.

Step 7: Update your disaster recovery plan regularly

Ensure that your AD disaster recovery plan is regularly updated in order to adapt to the ever-changing nature of your IT ecosystem. It is important to consider any changes in systems, processes, team composition, or contact information. Every test run should contribute to the refinement and clarification of the plan. Additionally, stay vigilant for any new compliance mandates or updated business requirements. The applications that held the highest importance yesterday may not be the same as today and this can impact the prioritization of Active Directory recovery operations.

Step 8: Perform initial recovery & redeploy remaining DC’s

To ensure optimal results, it is recommended to restore the forest and one Domain Controller to a separate network. After verifying the functionality of the forest/domain, you can then connect this isolated network to the production network. Broadly speaking, the high-level tasks involved are as follows:

1. Restore the initial writeable domain controller in each domain.
2. Reestablish connection for each restored writeable domain controller to the network.
3. Include the global catalog on a domain controller within the forest root domain.

Once all verifications are complete, it is time to redeploy all the remaining cleaned DCs during the initial recovery phase. To save time, you may want to consider using a W2012 PDC (or newer) and virtualization DC cloning. Finally, once you’ve restored the forest to its previous state, you may need to recreate any lost objects (users and computers) and reapply any missing updates.

Active Directory Disaster Recovery Best Practices

Below are some tips that can help with proactive Active Directory disaster recovery.

Acknowledge the shift in the threat landscape

In the past, recovering Active Directory from scratch was uncommon. However, due to the increase in ransomware attacks and other sophisticated threats that have appeared in recent years, the possibility of losing your entire Active Directory is now substantial. What was once rare is now a frequent occurrence. To recover from such an attack, your business should be ready in advance. This involves keeping secure and separate backups of your Active Directory environment, as well as incorporating Active Directory into your broader business continuity plan.

Restore Active Directory data onto a clean environment

While Active Directory disaster recovery is a complex process, the good news is that it is becoming less complicated in many respects, thanks to the availability of third-party security and recovery solutions. As long as your organization utilizes the appropriate tools, the primary challenge today involves assessing the various recovery scenarios. For instance, if your system has been infected with harmful software, restoring potentially compromised systems may inadvertently reintroduce the malware. A better option would be to reinstall a clean version of your OS, followed by a distinct process for forest recovery that involves restoring data from alternative backups.

Understand why Active Directory is a prime target for threat actors

Intruders who gain unauthorized access to a network typically start with low-level privileges since they have only compromised a single device or account. This is usually achieved through phishing or exploiting a zero-day vulnerability. To elevate their credentials, attackers often turn to Active Directory. This is because standard domain users have read permissions that give them access to configuration settings. A threat actor can exploit this vulnerability to gain greater privileges and ultimately gain control of the network, with access to all resources.

Establish an incident response plan to speed up the recovery process

If Active Directory experiences a breakdown, all other systems are affected too. No one can access their accounts or communicate with others – leading to chaos. Therefore, it is crucial to develop and test an incident response plan (IRP) in advance. Attempting to come up with a solution while the incident is unfolding will just result in confusion.

Use automation to simplify complex disaster recovery tasks

With so many intricate steps and settings involved, it’s easy to make mistakes. Automating steps such as metadata clean-up can significantly reduce the risk of errors during high-pressure situations. Recovering Active Directory from backups is a challenging technical process that requires additional organizational processes before and after the recovery. By automating as much of the recovery process as possible, you can devote more attention to essential tasks.

Monitor Active Directory to spot the early signs of compromise

By using a real-time threat detection solution you can identify and address anomalies within your Active Directory environment in a timely manner, and thus prevent a potentially serious incident from unfolding. Many modern Active Directory auditing and security solutions use machine learning techniques to identify atypical activities, such as unusual configuration changes, or suspicious logon attempts, and provide real-time notifications to the administrator’s inbox or mobile app.