SC-34: NON-MODIFIABLE EXECUTABLE PROGRAMS
NOT SELECTED FOR INDUSTRIAL CONTROL SYSTEMS
The information system at [Assignment: organization-defined information system components]:
- a. Loads and executes the operating environment from hardware-enforced, read-only media; and
- b. Loads and executes [Assignment: organization-defined applications] from hardware-enforced, read-only media.
The term operating environment is defined as the specific code that hosts applications, for example, operating systems, executives, or monitors including virtual machine monitors (i.e., hypervisors). It can also include certain applications running directly on hardware platforms. Hardware-enforced, read-only media include, for example, Compact Disk-Recordable (CD-R)/Digital Video Disk-Recordable (DVD-R) disk drives and one-time programmable read-only memory. The use of non-modifiable storage ensures the integrity of software from the point of creation of the read-only image. The use of reprogrammable read-only memory can be accepted as read-only media provided: (i) integrity can be adequately protected from the point of initial writing to the insertion of the memory into the information system; and (ii) there are reliable hardware protections against reprogramming the memory while installed in organizational information systems.
RELATED CONTROLS: SC-34
SC-34 (1) NON-MODIFIABLE EXECUTABLE PROGRAMS | NO WRITABLE STORAGE
The organization employs [Assignment: organization-defined information system components] with no writeable storage that is persistent across component restart or power on/off.
This control enhancement: (i) eliminates the possibility of malicious code insertion via persistent, writeable storage within the designated information system components; and (ii) applies to both fixed and removable storage, with the latter being addressed directly or as specific restrictions imposed through access controls for mobile devices.
RELATED CONTROLS: SC-34 (1)
SC-34 (2) NON-MODIFIABLE EXECUTABLE PROGRAMS | INTEGRITY PROTECTION / READ-ONLY MEDIA
The organization protects the integrity of information prior to storage on read-only media and controls the media after such information has been recorded onto the media.
Security safeguards prevent the substitution of media into information systems or the reprogramming of programmable read-only media prior to installation into the systems. Security safeguards include, for example, a combination of prevention, detection, and response.
RELATED CONTROLS: SC-34 (2)
SC-34 (3) NON-MODIFIABLE EXECUTABLE PROGRAMS | HARDWARE-BASED PROTECTION
- (a) Employs hardware-based, write-protect for [Assignment: organization-defined information system firmware components]; and
- (b) Implements specific procedures for [Assignment: organization-defined authorized individuals] to manually disable hardware write-protect for firmware modifications and re-enable the write-protect prior to returning to operational mode.
Supplemental Guidance: NONE
- NIST Special Publication 800-82 | GUIDE TO INDUSTRIAL CONTROL SYSTEMS (ICS) SECURITY