When crafting regular expressions, you have to be careful to not make them susceptible to catastrophic backtracking, because that would allow a DOS attack using a specifically crafted input. In this short talk, I explain how catastrophic backtracking works, why it happens, and I give a few tips on how to avoid it.
I originally gave this presentation as a "tiny talk" at our October 2014 company meetup in Denver. Because I received a good amount of positive feedback for it, I decided to create this recording of the talk and put it online.
The "further reading" link at the end of the talk is regular-expressions.info/catastrophic.html.
For some great reading on regex matching, in particular without using backtracking, see Russ Cox' excellent series at swtch.com/~rsc/regexp/.