FutureFeed CMMC Education Series · Access Control
Access Control (AC) 3.1.6
The short version
If you’re responsible for CMMC compliance, here’s what this requirement comes down to. You need to:
- Give anyone with admin rights a second, regular account for everyday work (email, web, documents)
- Reserve the privileged account or role for actual admin and security tasks
- Make elevating to admin a deliberate step, not the default way people work
- Keep records showing privileged accounts aren’t used for routine work
If you already have those things and can prove them, you’re well on your way. Now let’s talk about what each one actually looks like.
In plain English
Even the people who need admin rights shouldn’t use them all day. Most of an administrator’s day is ordinary work: reading email, browsing the web, writing documents. None of that needs admin power. This control says to do that everyday work from a normal account, and switch to the privileged account or role only when you’re actually doing admin or security work.
Here’s why it matters. If an admin reads email while logged in as admin and clicks the wrong link, the attacker instantly has admin control over your environment. If that same click lands on a regular account, it’s a much smaller problem. Separating the two shrinks the blast radius of a bad day.
The “or roles” wording matters if you use role-based access: switching roles can do the same job as switching accounts, as long as the role change truly changes what the person, and their automated processes, can do.
Do everyday work from an everyday account. Save the powerful account for the powerful work.
Example. Your systems administrator has two logins: a regular account for email, browsing, and documents, and a separate admin account for managing servers and user accounts. She spends most of her day in the regular account. When she needs to add a user or change a setting, she signs into the admin account, does the task, and steps back out. If a phishing email catches her in the regular account, the attacker lands on a login that can’t run the environment. That’s the whole point.
What you need to have in place
To be compliant, each of those boxes needs to be real and repeatable:
- A separate non-privileged account (or a role that drops privileges) for each person who also holds admin access.
- Everyday work done from the regular account: email, web, and documents don’t touch the privileged account.
- Privileged accounts used only for admin and security tasks, not routine activity.
- Elevation as the exception, so people log in with normal access by default and step up only when a task requires it. Enforce it technically where you can.
- Records of who holds a separate admin account, plus logs showing privileged accounts aren’t used for routine work.
The idea is simple: the account that can run your environment should barely ever be logged in.
What you need to prove it
Think in three buckets. An assessor will want all three, so it helps to build them at the same time.
People
- The IT or security lead who owns the account model
- The admins who actually use two accounts, or role-based elevation
- Whoever reviews how privileged accounts are used
Tools
- An identity system that supports separate admin accounts or role elevation
- Logging that shows what privileged accounts are used for
- Somewhere the account model is documented
Documents
- A policy requiring non-privileged accounts for everyday, nonsecurity work
- A list of who has separate privileged and non-privileged accounts, or role-based elevation
- Logs or records showing privileged accounts are used only for admin and security tasks
- A note in your System Security Plan (SSP) describing the account model
You don’t need heavy tooling. You need to show that admins live in a regular account and step up only when the work requires it.
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When should I work on this
Build this right after 3.1.5. Once you’ve decided privilege should be rare, this control makes sure even the people who have it don’t expose it during routine work. Set it up when you first create admin accounts, because getting an admin into the two-account habit from day one is far easier than breaking a single-account habit later. It also pairs with the next control, which keeps regular users from running privileged functions at all.
Common challenges
Admins do everything from the admin account.
Why it happens: One login is convenient, so email and browsing happen in the same session that manages the servers.
Recommendation: Give each admin a second, regular account and keep all everyday work there.
The second account exists but nobody uses it.
Why it happens: Switching feels like friction, so people just stay signed in as admin.
Recommendation: Make the regular account the default and elevate only for admin tasks. Enforce it technically where you can.
You can’t tell what the admin account is used for.
Why it happens: Nothing separates routine activity from real admin actions in the logs.
Recommendation: Log privileged-account activity so you can show it’s used only for admin and security work.
What good looks like
A compliant contractor can usually answer yes to all of these:
- Does each admin have a separate, non-privileged account for everyday work?
- Is routine work (email, web, documents) done from the non-privileged account?
- Are privileged accounts or roles used only for admin and security tasks?
- Can you show that privileged accounts aren’t used for routine activity?
If any answer is no, that’s your next place to start.
Watch out
Watch out: This isn’t about having fewer admins; that’s the previous control. It’s about how the admins you do have spend their day. Even a perfectly justified admin account becomes a liability the moment it’s used to read email and browse the web. And if you rely on role switching instead of separate accounts, the role change has to truly change what the person and their processes can do, or it doesn’t count.
How this connects to other controls
This control doesn’t stand alone. A few close relationships:
- Least privilege (3.1.5): that control keeps privilege rare; this one keeps even that privilege out of everyday use.
- Privileged functions (3.1.7): the next control keeps non-privileged users from running privileged functions at all, and captures it when they try.
- Audit & Accountability: logging is how you show a privileged account is used only for admin and security work.
The requirement, word for word
For your reference, here’s the exact language so you’re working from the source and not a paraphrase:
- 3.1.6 Use non-privileged accounts or roles when accessing nonsecurity functions.
Source: NIST SP 800-171 Rev 2, Access Control (3.1)
Related requirements: see also 3.1.5 (least privilege) and 3.1.7 (prevent
non-privileged users from executing privileged functions) within NIST SP 800-171
Rev 2.
Every organization implements these controls a little differently. If you’re not sure whether your approach would satisfy an assessor, join one of our upcoming webinars or schedule a 15 Minutes with FutureFeed session. We’d rather answer your questions now than have you discover them during an assessment.
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