Zero trust security models assume there are threat actors both inside and outside a network, and no access should be implicitly trusted. That goes beyond perimeter-based security approaches that rely on firewalls to prevent breaches. Instead, zero trust verifies all resource access continually and enforces strict identity, data and device security across applications and ecosystems.

In legacy perimeter models, users or systems that gain network entry through point authentication are free to then access approved resources without undergoing further identity checks. Once the barrier is breached, internal lateral attacker movement becomes difficult to control. Zero trust architectures mitigate this by treating even legitimate users as potential threats continuously.

Security principles dictate that mere location on a network does not determine level of access. Regardless of whether inside or outside the network perimeter, users have least privilege and can only access specific resources after passing dynamic authentication hurdles per attempt. Instead of static network checkpoints, micro-segmentation and granular access policies lock down data and workflows.

Multi-factor authentication (MFA), centralized identity provider management, end-to-end encryption and analytics-driven risk scoring govern access control decisions. Users must prove identity each session via rotating credentials on company-approved and secured devices before interacting with applications holding sensitive data. Firewalls and gateways still exist in zero trust models but serve mostly to enforce identity policies instead of acting as an entry barrier.

Zero trust increases visibility into all assets, users and network behaviors via unified logging, analytics, and automation. Suspicious activity triggers alerts and containment workflows. Practices like deceptively tagging files (“honeytokens”) further help detect unauthorized handling. That allows finding threats faster amid expanding cloud ecosystems, IoT and remote workforces operating outside the conventional perimeter.

The zero trust maxim of “never trust, always verify” provides a security-first approach suitable for application environments and workforces becoming more distributed and dynamic today due to digital transformation trends. The point is to neutralize attack vectors by removing assumptions and continuously validating connections.