Zero Trust

The classic model splits the world into inside and outside: whoever made it through the firewall counts as trustworthy. That model no longer holds with distributed teams, cloud services, and third-party devices - there is no inside any more, and a single compromised account opens everything behind it in a flat network.

Zero Trust replaces the question of location with the question of identity. Every access is verified on its own: who is making the request, from which device, to which resource, and is that plausible in this context? A service reading the customer database identifies itself to do so, regardless of which network it runs in.

In implementation the hardest part is rarely the technology but the permissions model underneath. Zero Trust forces the question of who actually needs to be able to do what - and in grown systems that question has often never been answered cleanly. The usual finding is that services and people may do considerably more than they need, simply because it was faster at setup time.

So a stepwise route pays off: first the accounts with the greatest damage on failure, then the breadth. A complete rebuild at once usually fails against day-to-day operations - and a security model that blocks the work gets bypassed.