This challenge, while technically a heap exploit is relatively easy. It is a simple buffer overflow in which the buffer that is supposedly "safe" is located directly after a user controlled buffer in the heap. Just like with a stack overflow, we can write past the bounds of our buffer and overwrite the "safe" buffer. The files and other items for this challenge can be found at the PicoGym under the challenge named "heap 0". I started as I always do by running "checksec" on the binary (pwntools required). Fortunately, the debugging info is left in which is convenient, but we have access to the source code anyway so its not super helpful. Unfortunately, the stack is not executable, and addresses are randomized, since we know from the name and description that this is a heap overflow challenge though that is not really too surprising. While I can't really capture it in blog form, my next step was to read through and understand every line of ...
