Hello. I'm Brian Mastenbrook. I'm an entrepreneur, security researcher, and open source developer.

Open Source

I work on a number of open source Common Lisp related projects in my free time. Here are some selected examples of projects that I have worked on:


Personal Creations

Educational History

Indiana University Department of Computer Science, 2003-2004. Graduate program in Computer Science. No degree recieved.

Roosevelt University, 1999-2003. Undergraduate program and Scholars Program. Received Bachelor of Science in Computer Science and Mathematics in 2003.


Frank Weil, Brian Mastenbrook, David Nelson, Paul Dietz, and Aswin van den Berg. Automated Semantic Analysis of Design Models. In ACM/IEEE 10th International Conference on Model Driven Engineering Languages and Systems (MoDELS), October 2007. PDF, 138 kB.

Thomas Weigert, Frank Weil, Kevin Marth, Paul Baker, Clive Jervis, Paul Dietz, Yexuan Gui, Aswin van den Berg, Kim Fleer, David Nelson, Michael Wells and Brian Mastenbrook. Experiences in Deploying Model-Driven Engineering. In SDL 2007: Design for Dependable Systems, September 2007.

Christophe Rhodes, Robert Strandh, and Brian Mastenbrook. Syntax Analysis in the Climacs Text Editor. Presented at the 2005 International Lisp Conference, San Francisco. PDF, 224 kB.

Brian Mastenbrook. A Formal Symbolic Framework for Structure-Based Reasoning. Honors Thesis, Roosevelt University, 2003. PDF, 872 kB.

Brian Mastenbrook and Eric Berkowitz. Evolutionary Incremental Concept Development for Case-Based Reasoning. Published as a Late-Breaking Paper at the 2003 Genetic and Evolutionary Computing Conference (GECCO), Chicago. PDF, 836 kB.

Eric Berkowitz and Brian Mastenbrook. Autonomous Generation of Grounded Spatial Primitives for Agent Reasoning and Communication. In Proceedings of the 2003 International Conference on Artificial Intelligence, June 2003. PDF, 40 kB.

Brian Mastenbrook and Eric Berkowitz. Representing Symbolic Reasoning. In Proceedings of the Fourteenth Midwest Artificial Intelligence and Cognitive Science (MAICS) Conference, April 2003. PDF, 172 kB.

Eric Berkowitz and Brian Mastenbrook. Grounded Concept Development Using Introspective Atoms. In Proceedings of the Fourteenth Midwest Artificial Intelligence and Cognitive Science (MAICS) Conference, April 2003. PDF, 56 kB.

Most recent blog:

Financial incentives for Mac malware

Posted on Sat, 26 Sep 2009
Last edited Sat, 26 Sep 2009
Apple's days of flying under the radar are over: there are now serious financial incentives for Mac malware. These incentives will spur development of drive-by malware as it's significantly more effective than trojans. OS X does not provide sufficient defenses against browser-based threats: I've found too many issues that could be used for drive-by malware installation just through simple logic errors that should have been flagged in code review.

If you're a researcher and would like to see where the problem areas, I wrote up a guide to finding issues on OS X earlier this year. Everything listed in this article is still applicable on Snow Leopard.