Why is the overwhelming majority of networked software still not secure, despite all effort to the contrary? Why is it almost certain to get exploited so long as attackers can craft its inputs? Why is it the case that no amount of effort seems enough to fix software that must speak certain protocols?
The answer to these questions is that for many protocols and services currently in use on the Internet, the problem of recognizing and validating their “good”, expected inputs from bad ones is either not well-posed or is undecidable (i.e., no algorithm can exist to solve it in the general case), which means that their implementations cannot even be comprehensively tested, let alone automatically checked for weaknesses or correctness. The designers’ desire for more functionality has made these protocols effectively unsecurable.
In this talk we’ll draw a direct connection between this ubiquitous insecurity and basic computer science concepts of Turing completeness and theory of languages. We will show how well-meant protocol designs are doomed to their implementations becoming clusters of 0day, and will show where to look for these 0day. We will also discuss simple principles of how to avoid designing such protocols.
Sergey Bratus is a Research Assistant Professor the Computer Science Dept. at Dartmouth College. His research interests include designing new operating system and hardware-based features to support more expressive and developer-friendly debugging, secure programming and reverse engineering; Linux kernel security (kernel exploits, LKM rootkits, and hardening patches); data organization and other AI techniques for better log and traffic analysis; and all kinds of wired and wireless network hacking.
Before coming to Dartmouth, he worked on statistical learning methods for natural text processing and information extraction at BBN Technologies. He has a Ph.D. in Mathematics from Northeastern University.
Meredith L. Patterson is a software engineer at Red Lambda. She developed the first language-theoretic defense against SQL injection in 2005 as a PhD student at the University of Iowa, and has continued expanding the technique ever since. She lives in Brussels, Belgium.
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