picoCTF 2022 | buffer overflow 0 Write-up

Challenge description

Smash the stack Let’s start off simple, can you overflow the correct buffer? The program is available here. You can view source here. And connect with it using: nc saturn.picoctf.net 65445

Category: Binary Exploitation


This is a very basic buffer overflow challenge. Let’s look at the program’s source code:

An interesting clue regarding the flag

Reading this, and knowing that a buffer overflow will cause a segmentation fault, my intuition is that the flag will be printed out in the event of a segmentation fault. Let’s keep going.

The buffer for our input is 100 bytes

Simple enough, I’ll just throw 101 characters at the program. You can type it out or use any method of generating random text.

And like that, the flag is ours

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