Zeus - DownUnderCTF 2025

Beginner/Zeus - jzt

To Zeus Maimaktes, Zeus who comes when the north wind blows, we offer our praise, we make you welcome!

Initial Thoughts

We are given an ELF binary. The first step, as with any rev challenge, is to decompile it.

Methodology

After putting the binary into Binja, we find the main logic of it.

When you run the binary, you have to add a -invocation with a value equal to var_10 for it to print the flag.

Scrolling up in the binary finds the full value of var_10.

Now it’s time to run the binary using my trusty Kali VM.

Solution

The flag is DUCTF{king_of_the_olympian_gods_and_god_of_the_sky}.