VPN appliances have become one of the most reliable entry points for ransomware operations against medium and large businesses. The economics are excellent for the attacker. A single working exploit can be reused against thousands of organisations that have not yet patched. The compromised appliance typically holds privileged access to internal networks. Detection on the device itself tends to be minimal. The result is a near perfect launchpad for the rest of the intrusion.
Patching Lags Behind Disclosure
Edge appliances often sit outside the regular patching cycle that covers desktops and servers. They are managed by network teams rather than endpoint teams, the upgrade procedure is more invasive and the perceived risk of changing a working appliance is high. The result is that patches available for months often remain unapplied long after threat actors have weaponised the underlying vulnerability. A focused external network pen testing engagement should validate the patching position on every internet facing appliance, not just the servers behind them.
Credentials Get Stolen Through Side Channels
Even where the appliance itself is patched, the credentials used to authenticate against it tend to leak through other routes. Phishing, infostealer malware on user workstations and previously breached password reuse all produce viable credentials for VPN access. Multi factor authentication mitigates this significantly but only when it is genuinely enforced and not exempt for service accounts or legacy clients.
Expert Commentary
William Fieldhouse, Director of Aardwolf Security Ltd
The ransomware investigations that trace back to a VPN appliance tend to share a profile. The appliance was running a known vulnerable version. Authentication did not enforce MFA on every account. The appliance held network access at a higher privilege than the average user actually required. Each of those decisions, taken in isolation, looked reasonable at the time. Together they were the door.
Zero Trust Network Access As An Alternative
Zero trust network access products replace traditional VPN connections with identity-aware proxy access to specific applications. The user authenticates, the device posture is checked, the application is accessed without the user ever joining the broader corporate network. The shift addresses many of the issues that VPN concentrators have introduced. Migration is non-trivial but the security improvement is meaningful for organisations large enough to justify the platform investment. Worth running pilot deployments to validate the user experience and operational model before committing to a full rollout. The technical capability is mature. The change management around the user transition is where most ZTNA deployments encounter friction.
Network Access Controls Limit The Damage
A VPN connection should not deliver broad internal network access. Identity aware access proxies, micro-segmentation and zero trust network access patterns all reduce the consequences of a compromised VPN session. Combine these with a routine best pen testing company that runs end-to-end attack scenarios from the VPN inward and the blast radius of a future compromise shrinks meaningfully.
The VPN was a convenient on-ramp to the office in 2010. In 2026 it is a convenient on-ramp for ransomware. Worth treating accordingly. VPN appliances will remain a high value target until the alternatives are universally deployed. Treat them with the respect that value implies. Network security has changed considerably over the last decade and the principles that survived the change tend to be the ones worth investing in. The fundamentals remain valuable even as the implementation details evolve around them.
