Adopt zero-trust architecture: verify every request regardless of network origin

The SolarWinds attack compromised the trust that internal network location implies authorisation. Once inside a network via a malicious software update, the attackers moved freely because internal systems implicitly trusted each other. Zero-trust architecture removes that assumption: every request, regardless of whether it originates from inside or outside the network perimeter, must be authenticated, authorised, and continuously validated. Implement micro-segmentation, require MFA for all internal application access, enforce device health checks before granting access, and log all east-west traffic.