Menlo Security Inc. has come up with a unique way to set itself apart from the scores of other startups promising to help companies defend themselves against hackers that may block one of the most widely-abused attack vectors in the enterprise once and for all. Its service, which launched this morning, allows workers to click even the most suspicious of emails without fear of infection.

The Menlo Security Isolation Platform, or MISP for short, accomplishes that using special virtual machines that each acts as a fully-contained sandbox for opening messages. That’s the same general concept as that behind the desktop virtualization services used to help make business applications available outside the office, with one major difference.

Content accessed in the service passes through a patent-pending filter before being rendered on the recipient’s device that not only strips away malicious elements but also optimizes delivery to improve the experience, according to the startup. That means Flash attachments are converted into a form that avoids animation stutter while Java code is executed with performance in mind.

What ends up arriving in the target browser is sterile code free of anything even remotely resembling malicious instructions. Web pages that users open through email links receive the same treatment, which closes off the last major path for hackers to try and exploit. That is, except phishing, although Menlo addresses that too indirectly.

Its technology is available either as a cloud service or as a standalone platform that administrators can implement behind the firewall in conjunction with their existing email security mechanisms to verify that reliable-looking messages come where they appear to be from. That on-premise option is particularly useful in heavily regulated segments such as the public sector where some communications can’t leave the four walls of the organization.

That value proposition has earned Menlo several dozen customers and the attention of the venture capital community, which added another $25 million to its coffers on occasion of the launch, The round was led by Sutter Hill Ventures with participation from existing investors and will help the startup hire more employees.

Photo by Skley.