goto-zero: An extended intro to solving stack overflow CTF challenges

Hey all! My husband’s company recently did an internal (commercial) CTF, and as a CTF nerd I got suckered into helping him. I thought one of the challenges had a pretty interesting solution - at least, something I hadn’t done before - and I thought I’d do a little write-up! Because it’s a commercial CTF, I wrote my own vulnerability binary, which you can grab here. It’s much, much simpler, but has all the components I wanted. They also provided libc.so, but since I’m not actually running the challenge, you can just use your own copy. (Note that I’m running the BSidesSF CTF again this spring, and will probably gussy up this challenge a bit and throw it in - don’t let a good challenge go unwasted!)