GopherHack Meeting 2024-09-25

Last week: format string

Tools to have:

• Access to an x86-64 Linux machine
  • CSELabs: click the link and run ssh <x500>@<machine>
  • WSL, Virtual machine
• netcat

We were working on a Format String problem from PicoCTF 2024.

nc gopherhack.easyctf.com 5013

The interesting part is that it does a printf(buf), which allows you to put whatever string you want.

One-liners from last week

To download a file, right click and copy paste the URL. Then, run:

wget -O <filename> <url>

To give yourself permission to run a binary, run:

chmod +x <file>

This week’s challenge: buffer overflow

Tools to have:

• Access to an x86-64 Linux machine
• Python
• GDB
• pwntools
• radare2 (optional)
• Cutter (optional)

Access the challenge at our contest site: https://gopherhack.easyctf.com/

nc gopherhack.easyctf.com 5015

How can we change the value of key?