Protected Users - Secure Your Credentials Against Mimikatz & Co

In the world of technology, information security is a constant concern. For those of us managing enterprise networks, protecting user credentials is a top priority. Today, I’ll introduce you to a special group in Active Directory (AD) - the “Protected Users” group, and why its use is crucial in our fight against attack tools like Mimikatz.

What is the “Protected Users” Group?

Introduced in Windows Server 2012 R2, the “Protected Users” group is a security feature in Active Directory that provides additional protection for user accounts. Adding a user account to this group enables enhanced security policies, limiting the ways in which credentials can be compromised.

The Threat of Mimikatz

To understand the importance of the “Protected Users” group, we must first know about Mimikatz. Mimikatz is a notorious hacking tool that allows attackers to retrieve passwords, password hashes, and other credential types from Windows memory. It is a powerful tool in a cybercriminal’s arsenal for carrying out “pass-the-hash” or “pass-the-ticket” attacks.

Why Use the “Protected Users” Group?

1. Enhanced Authentication Security: Members of the “Protected Users” group benefit from stricter security measures. For example, they cannot authenticate using older, less secure authentication methods such as NTLM, WDigest, or CredSSP.
2. Protection Against Pass-the-Hash/Ticket Attacks: Mimikatz and similar tools often exploit these legacy authentication methods. By restricting their use, the risk is significantly reduced.
3. Reduced Attack Surface: Accounts in the “Protected Users” group do not store reusable credentials in memory, making credential dumping attacks much less effective.

Implementation and Best Practices

1. Server Version: Ensure your AD environment is running Windows Server 2012 R2 or later.
2. Selecting Accounts: Do not add all user accounts to this group. Start with high-privilege accounts like administrators.
3. Password Policy: Encourage or enforce strong passwords and multi-factor authentication for accounts in the group.
4. Test Before Deployment: Test settings on a small number of accounts before applying them broadly.
5. Training and Awareness: Inform users about the changes and best security practices.

In conclusion, using the “Protected Users” group in Active Directory is a critical step in strengthening user credential security. By limiting the use of outdated and vulnerable authentication methods and reducing the attack surface exploited by tools like Mimikatz, you can significantly enhance your network’s security.

Remember, cybersecurity is an ongoing and evolving process. Adding accounts to the “Protected Users” group is one measure among many and should be part of a broader security strategy, including regular user training, continuous system updates, and proactive monitoring.

As IT professionals, our role is to stay vigilant and proactive. Making smart use of the “Protected Users” group is a step in the right direction to stay ahead of threats. Let’s work together to secure our digital environment.

Enjoy 😎

AlexIn Tech