An Email Worm Vaccine Architecture
Source: Columbia University
The authors present an architecture for detecting "Zero-day" worms and viruses in incoming email. Their main idea is to intercept every incoming message, pre-scan it for potentially dangerous attachments, and only deliver messages that are deemed safe. Unlike traditional scanning techniques that rely on some form of pattern matching (signatures), they use behavior-based anomaly detection. Under their approach, they "Open" all suspicious attachments inside an instrumented virtual machine looking for dangerous actions, such as writing to the Windows registry, and flag suspicious messages. The attachment processing can be offloaded to a cluster of ancillary machines (as many as are needed to keep up with a site's email load), thus not imposing any computational load on the mail server.