NIST SP 800-53 Rev 5 binds US federal systems, and reaches other organizations through contracts and flow down clauses. For everyone else it is a reference catalog: a detailed, public description of what a control can look like. PE-22, Component Marking, is one of the quietest controls in the Physical and Environmental Protection family.
The statement is short. Mark hardware components to show the impact level or classification level of the information the component is permitted to process, store, or transmit. The guidance names input and output devices: desktops, notebooks, keyboards, tablets, phones, printers, monitors, fax machines, scanners, copiers, and audio devices.
What it means in practice
Picture a shared printer room. One printer sits on the network that handles regulated customer data. Another sits on the guest network. If both look the same, someone will print a payroll file on the wrong one.
Marking fixes that with a label a person can read. The guidance separates marking (human readable security attributes) from labeling (attributes inside system data structures). PE-22 is about the first kind.
The guidance also says marking is generally not required for components that handle public information. You decide where the line sits and write it down.
Evidence to collect
- A written rule that says which components get marked and what the marks mean.
- Photos or a walk through of marked devices in at least two locations.
- An asset inventory column that records the data level each device is allowed to handle.
- Purchase or provisioning steps that include applying the mark.
Common gaps
- The rule exists but nothing is physically labeled.
- Labels were applied once and never checked after devices moved.
- Marks exist on laptops but not on printers, scanners, or conference room displays.
- No link between the mark and the permissions that control output (the guidance points to AC-3 and AC-4 for those).
How to implement it
Pick two or three levels that match your data classification, such as public, internal, and restricted. Print durable labels. Apply them at provisioning. Add the level to your inventory so a spot check compares the label to the record.
For a small company with no classified work, a short rule plus labels on shared output devices and restricted workstations is a reasonable reading of the control.
Quick check
Does PE-22 apply if we have no classified data?
The control speaks of impact level or classification level. You can map those to your own data classes. The guidance says marking is generally not needed for public information, so scope it to the devices that touch sensitive data.
