In the early days of remote work, client VPNs (Virtual Private Networks) were a game-changer. They’re essentially software tools installed on devices like laptops or phones that create a secure “tunnel” back to your company’s network. Employees use them when working from home, coffee shops, or traveling—basically anytime they’re not in the office—to access internal resources like files, emails, or applications. The “why” boils down to security and convenience: VPNs encrypt data in transit, protecting it from eavesdroppers on public Wi-Fi, and they make remote users feel like they’re on the office LAN. This was huge in the 90s and 2000s when perimeter-based security (like firewalls) ruled, and threats were mostly external.
But times have changed. With the rise of cloud services, mobile workforces, and sophisticated cyber threats, client VPNs have shown their age. Enter Zero Trust Network Access (ZTNA), an evolved approach designed specifically to tackle the inherent security flaws in traditional VPNs. ZTNA builds on the “zero trust” philosophy—never assume anything is safe, always verify—pioneered by frameworks like those from NIST. It shifts from broad network access to granular, context-aware controls, making it ideal for today’s hybrid environments where data lives everywhere.
The Hidden Risks of Client VPNs: Secure on the Surface, Vulnerable Underneath
At first glance, client VPNs seem solid because they encrypt your internet traffic, scrambling it so hackers can’t read it while it’s traveling from your device to the company server. That’s like putting your mail in a locked envelope before sending it. But here’s where they fall short, explained simply for anyone who’s not a tech whiz:
- No Boundaries Once Inside: A VPN gives your device full access to the entire network, as if you’re plugged in at the office. If a bad actor (or even a compromised employee device) gets through the initial login, they can roam freely—poking around servers, files, or other systems they shouldn’t. It’s like giving someone a key to the whole building when they only need the conference room.
- No Device Health Check: VPNs don’t inspect your laptop or phone before letting it connect. If your device is infected with malware (like a virus or ransomware), the VPN happily lets it in, potentially spreading the infection across the network. Imagine inviting a guest over without checking if they’re carrying a cold—they could infect everyone inside.
These issues have led to real-world breaches, where attackers exploit VPN vulnerabilities to gain a foothold and move laterally. As remote work exploded post-2020, VPNs became prime targets, prompting the evolution of ZTNA to plug these gaps.
Why Switch to ZTNA? A Smarter, Safer Alternative
ZTNA flips the script by assuming zero trust for every device, user, application, and service—no free passes. Vendors like Sophos and Fortinet offer robust ZTNA solutions that go beyond encryption. For instance:
- Before allowing any connection, ZTNA checks your workstation (laptop, etc.) to ensure it’s free from infections or vulnerabilities. Sophos ZTNA integrates with its Intercept X endpoint protection to validate device health, blocking access if threats are detected. Similarly, Fortinet’s Universal ZTNA uses FortiClient to perform ongoing posture checks, like verifying antivirus is running and no critical vulnerabilities exist.
- Once cleared, ZTNA creates an encrypted tunnel only to the specific app or resource you need—not the whole network. This limits damage if something goes wrong.
- Authentication is mandatory and continuous: You prove who you are (via multi-factor auth, certificates, etc.) for every session, and ZTNA re-verifies as needed. Both Sophos and Fortinet support this with identity providers like Microsoft Azure or Okta, ensuring only authorized users get in.
In short, ZTNA treats every request like a new one, verifying user identity, device posture, and context before granting access. This reduces your attack surface, prevents lateral movement by threats, and scales easily for cloud-heavy setups—without the headaches of managing VPN clients.
ZTNA vs. Client VPN: A Side-by-Side Security Comparison
To make it clear, here’s a table breaking down key security features:
| Feature | Client VPN | ZTNA (e.g., Sophos, Fortinet) |
|---|---|---|
| Encryption | Yes, encrypts traffic in transit. | Yes, encrypts traffic, often with granular per-app tunnels. |
| Access Control | Broad network access once connected; limited segmentation. | Granular, per-app access; assumes zero trust and verifies every request. |
| Device Posture Check | No built-in check for infections or vulnerabilities before connecting. | Yes, scans for malware, vulnerabilities, and compliance (e.g., AV enabled) before and during access. |
| Authentication | One-time login; no continuous verification. | Continuous, multi-factor; re-verifies user and device posture in real-time. |
| Lateral Movement Prevention | High risk; full network exposure allows threats to spread. | Low risk; micro-segmentation isolates access, blocking unauthorized movement. |
| Scalability for Hybrid/Cloud | Clunky for distributed resources; requires multiple VPNs. | Built for it; seamless across on-prem, cloud, and remote users. |
| User Experience | Can be frustrating with constant reconnects and full-network routing. | Transparent and frictionless; “just works” without broad exposure. |
Switching to ZTNA isn’t just about better security—it’s about future-proofing your setup against evolving threats like ransomware, which often exploit VPN weaknesses.
At Twotrees, we’ve helped countless clients transition to ZTNA solutions from Sophos and Fortinet, boosting their security without disrupting workflows. If you’re still relying on outdated VPNs, now’s the time to evolve. Contact us for a free consultation on making the switch seamless.
