With remote and bring-your-own-device (BYOD) access now commonplace, applying zero trust principles to Active Directory security is more crucial than ever. Enforcing least privilege access, adding MFA to password resets, scanning for compromised credentials, and more are key steps.
The traditional castle-and-moat approach to cybersecurity is no longer sufficient given today’s remote and mobile workforce trends.
With users accessing corporate resources from various devices and networks, organizations can’t fully trust entities based on their location within the corporate perimeter. This reality is pushing many to adopt a zero-trust model.
What is an Active Directory?
Active Directory is like an online phone book for an organization’s network. It is a database that stores information about all the devices and users within the network.
Within Active Directory, everything is an object – users, computers, printers etc. Each object has attributes that define it, like a username or IP address. Objects also have permissions that specify what they can access.
The key roles of Active Directory are:
- Authentication: Checking user credentials when they login and allowing access if valid.
- Authorization: Controlling what resources and apps each user has access permissions for.
- Lookup: Enabling users to easily find resources like shared files and printers via search.
So in basic terms, Active Directory allows centralized management of user identities and access controls in one dashboard. It’s the central configuration database that underpins key network functions like login, resource lookup and permission management.
Think of it like a library catalog and circulation desk in one – it catalogs all library items (network objects) and also handles check in/out (authentication and access control) for those items.
What is Zero Trust Security?
The zero trust model is an approach to cybersecurity that operates on the principle of “never trust, always verify”. It assumes no implicit trust in any user, device, or network—even those inside an organization’s own network perimeter.
All users, devices, and networks must be authenticated and authorized before being granted access to applications and data. This includes employees connecting from the corporate network as well as third parties.
As the backbone of authentication and access control, Active Directory plays an integral role in zero-trust frameworks. Ensuring Active Directory credentials and access are hardened as per zero trust tenets is therefore critical.
Here we detail some key best practices for achieving zero trust security in Active Directory. I should note that achieving zero trust is an ongoing process, and there’s no one solution that fits all.
1. Implement The Principle of Least Privilege
Privileged accounts pose an inherent security risk. Administrators may accidentally or deliberately misuse extensive rights in ways regular users cannot. More critically, if malicious actors compromise administrator credentials, they can inflict serious damage.
To mitigate this risk, organizations must enforce the principle of least privilege – restricting access to the bare minimum needed for any user or system. This principle limits potential impact from compromised accounts or insider threats.
Also Read: Cyber Defenses and Cyber Insurance: A holistic approach to cyber risk management
For Active Directory, implementing least privilege means ensuring each identity only has essential permissions. This shrinks attack surfaces by minimizing the damage any breach can inflict.
Transitioning to a zero trust model takes this further – requiring continuous re-verification of administrator access. Elevated privileges are only temporary, granted on a just-in-time basis when absolutely necessary.
Automated solutions can enforce limited privilege periods, disable dormant admin accounts, and adapt access based on context.
2. Use MFA for Password Resets
Password resets pose a glaring vulnerability in Active Directory security. Sending reset links or codes to user emails and phones invites exploitation. Attackers gaining access to these accounts can override the owner’s password.
Without multifactor authentication (MFA), unauthorized password resets threaten data exposure through account takeovers.
This weakness enables social engineering assaults on help desks. By posing as legitimate users, hackers can get reset links sent to devices they control instead. Such ploys were evident in the 2020 MGM Resorts breach, where callers obtained login credentials used to deploy ransomware.
MFA adds crucial identity confirmation beyond standalone passwords or codes vulnerable to interception. Integrating MFA into self-service password reset portals is therefore pivotal to securing Active Directory per zero trust principles.
Additional biometric or authenticator-based checks create layered defenses against unauthorized password changes, thwarting account hijacks and downstream data breaches.
3. Continuously Scan for Compromised Credentials
Despite complex passwords or MFA, credentials still get exposed via phishing, breaches, and reuse. Running frequent scans to uncover compromised Active Directory passwords that may allow unauthorized access is therefore vital.
This ensures leaked passwords can’t be utilized by malicious actors to bypass implemented zero trust mechanisms.
4. Evolve Towards Agentless Authentication
Agent-based authentication methods like VPNs often have vulnerabilities or visibility gaps compared to agentless zero trust approaches.
Over time, transitioning Active Directory authentication from old-school agents to modern standards like OAuth, SAML, and OpenID Connect allows for more robust, context-aware access controls aligned with zero trust ideals.
Conclusion
Achieving comprehensive zero trust worthiness is an iterative journey, but focusing first on locking down privileges, password security, and compromised credential detection establishes a foundational and expansive security posture.
Combining least access principles, MFA enforcement, and continuous password scanning sets the stage for further zero trust maturation across Active Directory.
