The NSA has issued guidance on adopting zero-trust principles to counter internal network threats. Zero-trust architecture prevents unauthorized access and movement within networks by assuming threats exist and enforcing strict access controls. The approach includes data flow mapping, segmentation, and software-defined networking to minimize breach impacts. No CVEs are associated with this guidance.
Security and efficiency make up 2 corners of an iron triangle. You generally have to sacrifice one of them to get the other (or increase the project cost/schedule).