When ransomware hijacks your active directory: an executive playbook

When ransomware hits, the instinct is to get systems back online as quickly as possible. But if the attack is on your Active Directory infrastructure, you must proceed with caution.

Rushing into recovery mode without full visibility into the impact may reintroduce malware, restore compromised configurations, or cause more damage than the initial attack.

Active Directory (AD) is foundational to 90% of large enterprise environments worldwide. It governs identity, enforces permissions, and serves as the gatekeeper for access.

If compromised, it puts a powerful business operations asset into the hands of attackers, who can disable security controls, escalate privileges, and expand their menacing foothold across the organization.

Recently, we’ve seen evidence of the scale of the threat posed to AD with the widespread zero day attacks mounted against Microsoft SharePoint.

A serious bug in SharePoint is being used by hackers to break into servers, steal security keys, and install hidden backdoors, prompting emergency fixes from Microsoft.

This isn’t just a SharePoint problem. It’s an identity threat in disguise, as attackers with basic site access can execute code remotely. No user clicks. No elevated rights. Just straight to the server.

And from there? If SharePoint is integrated with AD or Entra ID (as it often is), the Remote Code Execution (RCE) becomes a pivot point for infrastructure chaos.

Here is a playbook your organization should be ready to follow if ransomware ever compromises your domain controllers.

Contain first, react second

Containment is the first and most important priority. Before attempting recovery, the fastest way to stop additional damage is to cut the communications attackers rely on.

This means enforcing network-level blocks to immediately restrict the internal spread and lateral movement, while blocking all outbound traffic to stop communication with command-and-control servers.

Next on the priority list is to pause replication between sites and then disable automation that could propagate malicious changes.

Containment is not a passive step, it’s an active process to halt further damage and buy the time needed to assess what was accessed, what was altered, and how far the attack reached.

Recovering too quickly, especially from backups that haven’t been verified, can reintroduce the same vulnerabilities that attackers exploited in the first place.

That time you buy now will make all the difference later.

Investigate the real impact

Ransomware operators rarely kick the door in. They walk in with valid credentials. Phishing, password spraying, and stolen tokens are common entry points.

From there, they look for ways to escalate privileges using weak service accounts, legacy trust paths, or misconfigured permissions.

By the time ransomware detonates, they’ve already disabled logging, changed group policies, and planted backdoors in Active Directory.

This is where clarity matters. Don’t guess what was changed. In AD environments, attackers may:

• Create or modify privileged accounts
• Change group policies to weaken defenses
• Alter replication behavior to hide their activity
• Disable security logging or settings

Use AD-specific forensic tools to accurately detect changes. Investigate what’s been created, modified, or removed. If you're not sure how deep the compromise goes, assume it's deeper than you think.

Rebuild trust, not just systems

If Active Directory is rebuilt using compromised backups or without validating key services, the environment remains unstable and vulnerable.

The best approach is to already have an isolated recovery environment on standby ready to go in these moments.

Recovery of Active Directory is instant. However, if this is not something you already have in place, then you need to stand up in an isolated environment from which to recover.

Extensive testing will need to be performed to verify the backup predates the attack. Validate schema integrity, ensure healthy replication, and confirm policy consistency before restoring connectivity.

Restoring Active Directory is not just a technical milestone, it's a trust reset. If users and systems can’t rely on AD for secure authentication, business operations will continue to break down, regardless of how quickly services come back online.

To reduce complexity and risk, many organizations rely on solutions purpose-built for instant, clean AD forest recovery like those offered by vendors such as Cayosoft.

These tools are designed to eliminate guesswork, enforce best practices, and accelerate secure reintegration. The goal isn’t speed for its own sake, it's confidence that what you’re restoring is clean, stable, and trustworthy.

Harden from the core

A ransomware incident should prompt a full review of AD posture. Prevention is only effective if the environment is properly secured.

Here’s how to reduce your risk:

• Apply least privilege: No one gets more access than they need. Not users, not services, not even admins.
• Clean up old accounts: Disable or remove dormant users and machines. Rotate service account credentials.
• Audit your groups: Review high-privilege memberships and strip unnecessary access.
• Use tiered admin structures: Separate routine tasks from high-risk changes.
• Enable multi-factor authentication (MFA) ( across the board, especially for anyone touching identity infrastructure.

In parallel, improve visibility, as standard - event logging is rarely enough. Look for tools that detect subtle privilege escalation, unauthorized replication, and abnormal login patterns in real time.

Offline backups of domain controllers should be maintained and tested regularly. They remain the last line of defense in a full compromise.

Practice the recovery you promise

There’s a moment in every incident where someone says, “We’ve got a plan, right?”

And too often, the answer is, “We thought so.” Too often, organizations assume recovery will work, only to discover broken processes under pressure. It’s essential that all backups are immutable, encrypted and undergo daily validation and malware scanning.

Be sure to test restoration regularly, simulate domain controller rebuilds, verify that backups are not just complete but restorable, and train teams to execute the process under time constraints.

Recovery should occur in clean, isolated environments to prevent reinfection or reintroduction of compromised system state data. And critically, every recovery step should be documented, validated, and repeatable.

When AD is involved, recovery can’t just be a technical exercise. It must be a coordinated effort that demands clear leadership, cross-functional alignment, and discipline.

Make zero trust a culture, not just a framework

Once recovery is complete, the work shifts to building a more resilient environment.

Make zero-trust the baseline and stick to its principles, namely continuous identity verification, limited access by default, and monitoring that doesn’t stop at the perimeter.

You also need to start questioning long-standing assumptions about who and what should have access to critical systems.

You can support these efforts with red teaming which are simulated attacks to expose blind spots in your policies and tools.

These exercises often surface configuration drift, MFA exceptions, or legacy accounts that would otherwise go unnoticed.

A recovery plan that hasn’t been tested is a liability. A zero-trust model that hasn’t been challenged isn’t yet real.

Recovery starts before the attack

Ransomware is a stress test of your operations, leadership, and your organization's ability to stay functional under fire. When AD goes down, so does your ability to coordinate, communicate, and control access.

Effective recovery begins long before an attack. It starts with knowing where your weak points are, keeping your environment lean and visible, and practicing your response under controlled conditions. This starts with having a plan.

The most resilient teams contain quickly, investigate thoroughly, restore precisely, and evolve continuously. Ransomware doesn’t need to shape your future. It can be the catalyst for building greater resilience and regaining control.

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