system support function

A category of privileged IT activities — such as configuration management, quality assurance and testing, system management, programming, and network security — that must be distributed across multiple individuals or roles rather than concentrated in any one person. It is distinguished from mission or business functions by its technical/administrative character: these are the internal operational tasks that keep a system running and secure, as opposed to the outputs the system produces for the organization. In the field, the concept is invoked as one of the three main mechanisms for implementing separation of duties (NIST SP 800-53 AC-5; NIST SP 800-171 control 3.1.4), alongside dividing mission functions and preventing administrators from holding cross-cutting privileges such as both access-control administration and audit administration.