Simple Elf

This is a writeup of the reversing challenge Simple ELF from the Security Valley CTF

Premise

Can you deal with dwarfs and elfs`

Link: https://github.com/SecurityValley/PublicCTFChallenges/tree/master/reversing/the_elf

Challenge files:

crackme-01

Observations

When simply attempting to run the file, we get the following output:

Sometimes, there is something inside me. Can you get it?
S
Whoops, that was weird??

Which doesn’t allow us as users to do a lot, so we move on to another method.

Solution

If we run the strings command, simply:

strings crackme-01

We’re able to find our flag among the strings outputted. To simplify it even further, we can run:

strings crackme-01 | grep SecVal

When running the second command, we get the flag in plaintext: SecVal{[REDACTED]}

Tools used:

• A standard linux terminal
• strings
• grep