Quick answer: VPN security is protecting remote access with an encrypted tunnel while ensuring this tunnel itself is not a weakness; ZTNA (Zero Trust Network Access) is a newer approach that solves the fundamental problem of VPN. The biggest weakness of classic VPN is this: when a user connects to the VPN, they often gain access to the entire internal network; so a stolen VPN identity opens a broad area to the attacker. ZTNA reverses this: it gives the user access not to the whole network but only to the specific application they are authorized for and continuously verifies every access. The root fix is to protect the VPN with strong authentication and up to date configuration, but in the long term to move to the ZTNA model that shifts access from the network level to the application level.

As remote work becomes permanent, remote access security has become a critical topic. For years VPN was the standard answer, but VPN has a fundamental architectural weakness. This article explains VPN security, its weaknesses and the transition to ZTNA.

The fundamental weakness of VPN

A classic VPN connects a user to the internal network with a secure tunnel. The problem is that this connection often gives the user access to the entire internal network. That is, the VPN takes the authenticated user inside the network and grants broad trust there. When an attacker gets in with a stolen VPN identity or a flaw, they can now move across the entire internal network. This is the fundamental problem zero trust architecture tries to solve: automatically treating the inside as trusted.

VPN risks and ZTNA comparison

Dimension Classic VPN ZTNA
Access scope Entire internal network Only the authorized application
Trust model Verify once, trust inside Continuously verify
Lateral movement Broad after entry Limited at the application level
Visibility Limited Every access is monitored
Attack surface Open VPN endpoint Application hidden, not directly exposed

The essence of this comparison is: VPN gives access to the network, ZTNA gives access to the application. The difference is how much an attacker can move when they get in.

Keeping the VPN secure

The transition to ZTNA is a process; meanwhile, if VPN is used it must be kept secure:

  • Strong authentication. VPN access must be protected with multi factor authentication; a password alone is not enough.
  • Up to date configuration. VPN servers must be kept up to date against known flaws; VPN endpoints are targets attackers often scan.
  • Least access. Access after VPN must be limited to the needed sections with network segmentation, not the whole network.
  • Monitoring. VPN accesses must be logged and unusual behavior monitored.

Transition to ZTNA

ZTNA moves remote access from the network level to the application level. The user accesses not the network but only the application they are authorized for, and every access is continuously verified by identity and context. This greatly limits the impact of a stolen identity. The transition can be gradual: critical applications are moved to ZTNA first, VPN is narrowed over time. This is a modern application of identity and access management.

The KAOS and DSET approach

DSET assesses your remote access architecture for VPN security and the transition to ZTNA. The local AI engine KAOS tests the configuration and vulnerabilities of VPN endpoints, the strength of authentication and the access scope after VPN with an evidence first approach. It assesses whether the compromise of an identity would actually lead to broad lateral movement and reports only the real risk without false positive noise. The goal is to move remote access to an architecture that is both secure and sustainable.

Frequently asked questions

Is VPN insecure now? VPN is not insecure but has a fundamental architectural weakness: it often gives the authenticated user access to the entire internal network. With strong authentication, up to date configuration and least access, VPN can be kept secure; but in the long term ZTNA is a more solid model.

Does ZTNA fully replace VPN? It can largely replace it over time. Because ZTNA gives access at the application level instead of the network, it limits the impact of a stolen identity. The transition is usually gradual: critical applications are moved first, VPN is narrowed. Transition periods where both are used together for a while are common.

Should I shut down my VPN immediately? No, the transition is a process. Meanwhile, VPN must be kept secure with multi factor authentication, up to date configuration and least access. A gradual transition to ZTNA both increases security and prevents disruption.

Sources

To assess your remote access architecture for VPN security and the transition to ZTNA, contact DSET. We provide security assessment and penetration testing from our Ankara Hacettepe Teknokent laboratory.