Strengthening Privileged Session Manager security by removing the default Domain Users group

Why PSM hardening isn’t a buzzword — it’s a shield you can actually feel

If you’re navigating the world of CyberArk Sentry, you’ve probably heard the term Privileged Session Manager, or PSM. It sounds like tech theater, but it’s not about showmanship. It’s about cutting risk where it hides: the privileged sessions that let someone do powerful things in your environment. Hardening PSM is like tightening the bolts on a ship’s hull — a few precise actions can keep a lot of trouble at bay. And yes, one step in particular tends to stand out in conversations about reducing exposure: removing the default Domain Users group from certain privileges.

Let me explain why that one move matters so much.

The core idea: least privilege in practice

Here’s the thing with most domain environments: the Domain Users group is a broad umbrella. It includes thousands of accounts that aren’t intended to run critical operations, but in some setups, those accounts can slip into roles with elevated access or be used as a foothold if a system is compromised. When you’re hardening PSM, you’re aiming to limit who can start or manage privileged sessions and what they can do once they’re in. The principle of least privilege isn’t a vague guideline; it’s a concrete defense choice. If you can prevent a large, ordinary user base from inheriting elevated rights unintentionally, you’ve already pushed the risk down the road.

By removing the default Domain Users group from the access paths that feed into privileged sessions, you shrink the attack surface in two practical ways. First, you reduce the set of accounts that are even eligible to participate in sensitive tasks. Second, you force a more deliberate authentication and authorization process for those who truly need it. It’s a clean, auditable tightening of control that you can see in logs, not just in a policy doc.

A quick mental picture: imagine a busy, shared kitchen in an office building. The Domain Users group is like giving everyone a key to the kitchen. Some folks only need the coffee pot; others need the stove. If you remove the broad keyring from the kitchen’s restricted zones, you’re preventing accidental or malicious overuse. You still keep doors unlocked where there’s a real need, but you don’t hand the keys out to the whole building. That’s the essence of this PSM-focused move.

Why this step stands out among the other controls

Let’s glance at the alternatives you might see on a checklist:

• Adding users to the Domain Users group. This is essentially the opposite of hardening. It expands access, not restricts it. It’s a quick way to invite trouble if those accounts don’t truly need elevated access.

• Installing a new security patch. Patches matter, sure, but patching is about software health and vulnerability remediation. It doesn’t by itself address the risk created by over-broad group memberships in privileged pathways.

• Enabling Network Level Authentication (NLA). NLA is a solid hardening measure for remote sessions, but it doesn’t specifically fix the fundamental issue of who’s allowed to participate in privileged sessions. It’s a shield for the doorway, not the crowd inside the room.

The Domain Users group removal gets to the heart of who can even attempt privileged actions. It’s a targeted, preventive move that pays off by hardening the brain of the operation — the identity and authorization layer that governs access to sensitive commands and systems.

How to implement this thoughtfully within CyberArk Sentry (PSM)

If you’re responsible for a CyberArk environment, this is the kind of change you want to plan with care. It’s not a “flip a switch and hope for the best” moment. It’s an opportunity to align access with roles, evidence, and accountability.

Step-by-step ideas you can adapt

• Map who touches privileged sessions. Start by cataloging the accounts that participate in PSM-managed sessions and the systems those sessions touch. You’re looking for places where Domain Users might be implicitly included.

• Identify where Domain Users show up in privileges. In your PSM configuration, audit the groups tied to target access, session initiation, and any policy that governs who can approve or initiate a privileged session. If Domain Users is listed as a member in those privileges, you’ve found your target.

• Replace broad access with role-based controls. Instead of linking to Domain Users, use a defined set of roles that reflect actual job functions. That way, you can grant access on a need-to-do basis rather than a broad “everyone.” It’s not about creating a maze; it’s about clarity and accountability.

• Implement strict approval and auditing. Any change to who can access privileged sessions should be traceable. Turn on detailed logging for access requests, approvals, and session activity. When you need to adjust permissions, you’ll have evidence, not guesswork.

• Test with care. After you remove Domain Users from the relevant privileges, run tests with representative accounts (both elevated and standard) to confirm that legitimate administrators can still reach the tools they need, while unauthorized paths stay blocked. A good test doesn’t stall work; it clarifies what changed and why it’s better.

• Roll out gradually. It’s wise to phase the change, starting in non-production or a staging environment, then moving to production once confidence is high. Tracking metrics like failed access attempts or the rate of legitimate access helps you see the real impact.

• Keep a living policy. Privilege management isn’t a one-and-done project. As teams change and new systems come online, revisit who truly needs access to PSM-managed sessions. The landscape shifts; your controls should too.

The practical payoff

Think of the payoff in concrete terms. Fewer accounts with broad reach means fewer pathways an attacker can exploit to reach a sensitive system. It also makes your audits cleaner: who accessed what, when, and why becomes easier to verify. You’ll have a clearer line from a policy decision to a concrete security outcome. That’s the sweet spot where security feels both robust and humane — not an opaque fortress, but a well-lit, well-managed one.

A broader perspective: other related safeguards you can weave in

While removing the Domain Users group from sensitive privileges is a strong, focused measure, you don’t want to rely on a single control. Think of security as a chain with many links. Here are a few companion moves that fit naturally alongside PSM hardening:

• Patch management. Keeping systems up to date closes known gaps that could be exploited during privileged sessions. Scheduling timely patches helps reduce a surprising amount of risk without extra ceremony.

• Network Level Authentication and MFA. NLA adds a layer to verify identity before a session even starts. When combined with multi-factor authentication for admin accounts, it raises the price of entry for attackers without slowing down legitimate admins too much.

• Segmentation and least-privilege networking. If you can isolate critical servers or environments, even a compromised account has a narrower path to reach the crown jewels.

• Regular access reviews. Periodically re-certify who can initiate privileged sessions. A quarterly gut-check can reveal drift before it becomes a problem.

• Automated monitoring and alerting. Real-time alerts when unusual or unexpected session activity occurs help you catch issues early. Pair that with a fast, clear playbook for responding to incidents.

A practical mindset for the journey

If you’re reading this and thinking about your own CyberArk Sentry setup, you’re not alone. Privileged access is a high-stakes domain, but the work doesn’t have to feel like rocket science. The right changes, documented and tested, make a real difference. When you remove the default Domain Users group from privileged pathways, you aren’t just following a rule—you’re shaping a safer operational culture. You’re telling every user, “Those doors are guarded, so you use only what you need.”

A few mindful questions to keep in mind as you work

• Does every account in the privileged path truly need that access, or can it be reserved for a smaller subset of roles?

• Are we keeping enough visibility so an auditor or a security analyst can understand why access was granted or denied?

• If a compromise occurs, does our configuration help us trace the exact steps an attacker might have taken?

• Are we balancing security with day-to-day usability so engineers aren’t fighting with access controls every time they work?

A closing thought

Security isn’t about building a fortress that’s impossible to breach. It’s about building a system that’s predictable, auditable, and proportional to risk. The move to remove the default Domain Users group from privileged access is a crisp step in that direction. It embodies a disciplined approach: restrict where you can, verify what you must, and watch the results in real time.

If you’re involved in managing CyberArk Sentry and PSM, you’ll recognize the value of thoughtful adjustments like this. They’re not flashy, but they’re meaningful. They’re the kinds of details that quietly accumulate into stronger resilience, clearer governance, and, frankly, a calmer operating environment for everyone who depends on your security posture. And isn’t that what solid protection feels like — steady, reliable, and just a little bit smarter every day?