Postdeployment code dissemination in wireless sensor networks (WSN) is challenging, as the code has to be transmitted via energy-expensive wireless communication. In this article, we propose novel update-conscious compilation (UCC) techniques to achieve energy efficiency. By integrating the compilation decisions in generating the old binary, an update-conscious compiler strives to match the old decisions, which improves the binary code similarity, reduces the amount of transmitted data to remote sensors, and thus, consumes less energy. In this article, we develop update-conscious register allocation and data layout algorithms. Our experimental results show great improvements over the traditional, update-oblivious approaches.

The automatic patch-based exploit generation problem is: given a program P and a patched version of the program P', automatically generate an exploit for the potentially unknown vulnerability present in P but fixed in P'. In this paper, we propose techniques for automatic patch-based exploit generation, and show that our techniques can automatically generate exploits for 5 Microsoft programs based upon patches provided via Windows Update. Although our techniques may not work in all cases, a fundamental tenant of security is to conservatively estimate the capabilities of attackers. Thus, our results indicate that automatic patch-based exploit generation should be considered practical. One important security implication of our results is that current patch distribution schemes which stagger patch distribution over long time periods, such as Windows Update, may allow attackers who receive the patch first to compromise the significant fraction of vulnerable hosts who have not yet received the patch.

Wireless sensor networks (WSN), composed of a large number of low-cost, battery-powered sensors, have recently emerged as promising computing platforms for many non-traditional applications. The preloaded code on remote sensors often needs to be updated after deployment in order for the WSN to adapt to the changing demands from the users. Post-deployment code dissemination is challenging as the data are transmitted via battery-powered wireless communication. Recent studies show that the energy for sending a single bit is about the same as executing 1000 instructions in aWSN. Therefore it is important to achieve energy efficiency in code dissemination.