Answer
Zero trust security differs from perimeter-based security by rejecting the idea of a trusted internal network and requiring verification for every access request, regardless of origin. Perimeter-based models assume that once a user is inside the network, they are trusted, which allows attackers to move laterally after breaching the outer defenses.
In contrast, zero trust enforces strict identity verification and least-privilege access for every request, even from inside the network. This limits an attacker's ability to move sideways after gaining initial access. Policies are dynamic and based on device status, user role, and request context, making the system more resilient to insider threats and compromised credentials.