Cybersecurity / Remote Access
A legacy SSL VPN should no longer be treated as a secure default just because employees can connect and the traffic is encrypted. An exposed gateway, excessive access and an unsupported platform can turn a familiar remote-work tool into a serious business risk.
That does not make every SSL VPN unsafe. It means SSL VPN security depends on much more than the encrypted tunnel. For businesses still relying on older deployments, the case for moving to more tightly controlled access is getting harder to ignore.
The biggest SSL VPN security risks start at the gateway
A conventional internet-facing VPN gateway must handle incoming traffic before it knows who is connecting. Vulnerabilities in that software can give attackers an entry point before normal login protections apply.
Fortinet’s CVE-2023-27997, for example, allowed an unauthenticated attacker to execute code through specially crafted requests. MFA remains essential, but it cannot repair a flaw that is exploitable before authentication. Fortinet’s analysis explains the vulnerability and response.
The familiar “SSL VPN” label also does not mean modern implementations rely on obsolete SSL encryption; many use TLS. The concern here is vulnerable gateway software and access design, not evidence that TLS encryption has been broken.
Patching a VPN may not finish the recovery
On April 10, 2025, Fortinet disclosed that an attacker had used known vulnerabilities and left a filesystem link that could preserve read-only access after the original flaws were patched. Files exposed could include device configurations. Fortinet provided mitigations to remove the link. Fortinet’s incident analysis details the response.
The operational lesson matters: patch promptly, but investigate possible compromise separately. A current software version alone cannot establish that an earlier intrusion has been fully remediated.
Encrypted remote access can still grant too much access
Encryption protects data in transit. Access policies determine what a connected user or device can reach.
A broadly configured VPN may expose far more of the network than an employee needs. Segmentation and restrictive rules can reduce that risk, so broad access is not inevitable. But those controls need to be deliberately designed, tested and maintained.
NIST’s Zero Trust Architecture rejects automatic trust based on network location. The practical goal is to authorize access to the resources needed for the task, rather than treating a successful connection as permission to reach the wider network.
Vendor changes make SSL VPN migration a planning issue
Fortinet removed SSL VPN tunnel mode across FortiGate models beginning with FortiOS 7.6.3, directing that use case to IPsec VPN. This was not the removal of every SSL VPN-related feature. Fortinet release notes.
SonicWall’s SMA 210, SMA 410 and SMA 500v reached end of support on November 1, 2025. Its exceptional April 2026 license-management firmware release did not restore support. Those product retirements do not cover every SonicWall SSL VPN product. SonicWall’s notice and product lifecycle tables.
Check the exact model, software version and support status before planning an upgrade. Moving from SSL VPN to IPsec can address a product transition, but changing the tunnel protocol alone does not create Zero Trust.
SSL VPN alternatives: ZTNA and SASE
Zero Trust Network Access, or ZTNA, can restrict connections to authorized applications using identity, device condition and policy. Secure Access Service Edge, or SASE, combines networking with cloud-delivered security capabilities; ZTNA can be part of that architecture. CISA and its partners recommend evaluating modern access approaches as organizations’ needs evolve.
CTS is deploying SASE to help businesses move beyond legacy remote access. Properly implemented, it can provide significantly stronger protection than a broadly accessible legacy SSL VPN deployment by reducing unnecessary exposure and limiting what each connection can reach.
The improvement comes from those controls, not the acronym. Identity security, endpoint protection, configuration and monitoring still matter. During migration, keep the existing platform supported and patched, retain MFA and test application access before retiring the old connection.
Plan your next step
If your business still relies on an SSL VPN, talk with CTS about reviewing its risks and planning a move to modern, more secure remote access.