When you start a CMMC program, three kinds of provider show up and the acronyms blur together: the MSP, the MSSP, and the vCISO. They are not interchangeable, and hiring the wrong one for the job you actually have is a common — and expensive — mistake.
The MSP: runs your IT
A Managed Service Provider keeps your technology working — servers, endpoints, patching, help desk. Many defense contractors rely on one. But note two things: a general MSP is not automatically equipped for CMMC, and under the rules your MSP is itself an external service provider whose handling of your systems comes into scope. A good MSP is necessary; it is rarely sufficient on its own.
The MSSP: runs your security operations
A Managed Security Service Provider focuses on security operations — monitoring, alerting, log review, incident-response support. An MSSP helps you satisfy the operational, always-on requirements (audit and accountability, incident response) that a once-a-year effort cannot. It is a doing role, not a deciding role.
The vCISO: owns the strategy
A virtual (or fractional) CISO is the accountable security leader you rent instead of hiring full-time. The vCISO decides what your program should be — scope, risk decisions, the roadmap, the SSP and POA&M, answering a prime’s questionnaire — and directs the MSP and MSSP toward it. It is the head, where the other two are the hands.
How they fit
Most contractors need some of all three: an MSP to run IT, security operations (in-house or an MSSP) to run the controls, and a vCISO to own the program and keep it honest. The trap is expecting your MSP to also be your CISO — a strategy role no infrastructure contract was scoped to fill.