Writing a FedRAMP SSP: Structure, Boundaries, and Diagrams

The System Security Plan is the centerpiece of a FedRAMP package. It describes your system, draws its boundary, and explains how every control in your baseline is implemented.

What reviewers look for

• —A precise authorization boundary with a current architecture diagram and a data flow diagram.
• —A clear description of the service, its components, and the external services it depends on.
• —A control implementation for each control, including who is responsible — you, the cloud platform, or shared.
• —Consistent, specific language that matches the assessment evidence.

Describe shared responsibility honestly

If you build on an authorized IaaS/PaaS, say which controls you inherit, which you provide, and which are shared. Vague inheritance claims are a common cause of rework. Tie each to the provider’s customer responsibility matrix.

Diagrams do heavy lifting

A clean boundary diagram and data flow diagram answer half of a reviewer’s questions before they ask. Invest in them; keep them current as the architecture changes.