Understanding the Risks of SSL VPNs

In today’s fast-paced digital environment, enabling secure remote access for employees is a top priority for businesses of all sizes. For years, Secure Sockets Layer Virtual Private Networks (SSL VPNs) have been the go-to solution for providing employees with access to company resources from anywhere.

Their popularity is largely due to their ease of use, browser-based accessibility and straightforward deployment. However, as cyber threats evolve, traditional SSL VPNs have become a target for cybercriminals and are putting the organizations that use them at risk.

In 2025 alone, there have been several high profile SSL VPN attacks targeting devices from Ivanti, SonicWall, Fortinet, and Cisco. In response, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) added SSL VPN vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog.

Keep reading to learn more about SSL VPNs, how hackers are accessing these tools, and how you can secure your business and reduce your risk of cyberattack.

What Is an SSL VPN?

An SSL VPN is a tool that allows users to securely connect to a private network over the internet. It uses the same encryption protocol that powers websites to protect data as it travels between a user’s device and the corporate network.

Unlike traditional VPN solutions that require installing special client software, SSL VPNs work within a standard web browser. This makes them easy to use, quick to deploy and effective at helping employees access business resources remotely, even behind firewalls.

How Hackers Exploit SSL VPNs

Unfortunately, the very features that make SSL VPNs attractive to businesses have also made them a prime target for cybercriminals. Even businesses that regularly update their systems can fall victim to quickly emerging zero-day exploits or clever social engineering schemes. Our team at Atlas has been seeing more of these types of attacks in recent months.

The most common exploitation methods include:

• Vulnerability Exploitation: Hackers exploit known vulnerabilities and unpatched flaws (including “zero-day” vulnerabilities) in SSL VPN software. These can be memory corruption issues like buffer overflows or authentication bypasses that allow remote code execution, giving a hacker a foothold in the network without a valid login.
• Credential Theft: Cybercriminals use stolen or brute-force credentials to log in. Once authenticated, a malicious actor can gain broad access to the network, and the “trusted” nature of the VPN connection can make it difficult to detect them.
• Session Hijacking: Hackers hijack an existing, legitimate VPN session, bypassing the need for a login and gaining immediate access to the internal network.

Once inside, cybercriminals can move laterally across the network, escalate their privileges and deploy malware – such as ransomware – that puts the entire organization at risk. Unfortunately, the trusted nature of VPN connections means that these breaches can go undetected for extended periods, further increasing the damage potential.

What Businesses Should Do: Enhance Security Protocols

To reduce the risk of an attack, we recommend all business who use an SSL VPN enable multi-factor authentication (MFA) or two-factor authentication for all users. MFA requires users to provide at least two methods of authentication when logging into an application. This greatly reduces the risk of credential theft.

To simplify this for end-users, businesses can also set up SAML (Security Assertion Markup Language) authentication. This allows users to sign in once using a set of credentials – i.e. Microsoft 365 – and then access multiple applications. With SAML authentication, identity providers, like Microsoft Entra ID, verify users when they sign in and then pass that authentication data to other apps or services the users wish to access.

Using MFA or SAML authentication allows businesses to continue using the same SSL VPN without disrupting the user experience.

Conclusion

SSL VPNs have served businesses well, but the risks of relying on them continue to grow. Hackers become more adept at exploiting these systems. So, it’s time for organizations to rethink their approach to secure remote access.

By embracing more stringent protocols and partnering with knowledgeable IT professionals, your business can stay ahead of cyber threats and safeguard its most valuable assets. Don’t wait for a breach. Start planning your transition to a safer, smarter network today.

Ready to protect your organization from SSL VPN vulnerabilities? Contact Atlas Professional Services today to learn more about our cybersecurity solutions.