Shattered-Memories [LA CTF 2024]

Challenge Description

I swear I knew what the flag was, but I can’t seem to remember it anymore… can you dig it out from my inner psyche?

Intuition

Let’s open first the program using ghidra and see what we can find.

It seems the flag is split into different parts into the stack.

Solution

We can start looking at the first offset local_98 which is the lactf{no string in the Ghidra representation where this input is used int the strncmp function. Then because the stack use the LIFO method, we have to reconstruct the flag by taking the highest offset after local_98 which is acStack_90, then acStack_88 and so on. By looking on all those offset we can find the flag.

Flag

lactf{not_what_forgive_and_forget_means}