SC-25 Thin Nodes says to employ minimal functionality and information storage on system components you choose. The guidance names diskless nodes and thin client technologies. The idea is that if an endpoint holds nothing, there is less to steal and less to secure.
NIST SP 800-53 binds US federal systems, and reaches contractors and cloud providers through contract terms such as FedRAMP. For everyone else it is a reference catalog. Most small companies will use this control by choice, not because a contract forces it.
What it means in practice
You decide which components get thin treatment. Common choices are virtual desktops for contractors, kiosks, shared lab machines and administrative jump hosts. The data lives in a central service and the endpoint only displays it.
The trade is real. Thin nodes cost you offline use, and they concentrate risk in the central service. If the virtual desktop host falls over, everyone on it stops working. NIST's own wording says minimal functionality may reduce exposure, not that it removes it. Be ready to explain the central side of the design as well.
For small teams, a managed browser profile with enforced device encryption is a common middle path when full thin clients are too heavy.
Evidence to collect
- The list of components you declared thin, with the reason.
- Configuration showing local storage is disabled or wiped at logout.
- Virtual desktop or browser isolation settings.
- A sample device with no local copy of regulated data.
Common gaps
The declaration exists but the endpoint still syncs files locally. Another gap is a thin client with a full local admin account.
How to implement it
Pick one population, such as offshore contractors. Give them a managed virtual desktop, disable clipboard and download where policy allows, and test by trying to save a file locally.
Quick check
Do I need thin clients everywhere?
No. The control applies to components you name. Record which ones and why.
