If anybody face extreme problem !!! 1. use reverse engineering tool (Ghidra or binary ninja) , 2. After analyzing you will see , The program use the system call and use our input as it's argument/param without sanity check . For this , " command injection " can be applied 3. So , after nc in linux cat the flag ( ; cat flag.txt )

1. For those who want a hint, Decompile the source code you will find what is happening under the hood,
2. See what command it's trying to execute and learn about that command.
3. After finding the command, try how can you inject commands with that

eazy if somebody needs help just let me know

Ghidra :)

Just read the decompile

the solution is soo dumb.. i was stuck at this challenge for 3 days.. thought of some complex stuff.. in 10 point challenge.. but no.. the answer is simple and very very dumb.. anyone wanting hints... well.. no hints do it yourself.. its very easy

btw.. nice challenge.. researched and learnt a lot.. Thankyou..

hint please

Good challenge. For beginners: Whenever you are given executable, you must take a close look at it with proper tools...

I'm really stuck here tho, can u pls provide more hint about proper tool? I used wine but couldn't run it

There is another tool mentioned below, also you should definitely have IDA in your toolkit.

Good one!

the solution is soo dumb.. i was stuck at this challenge for 3 days.. thought of some complex stuff.. in 10 point challenge.. but no.. the answer is simple and very very dumb.. anyone wanting hints... well.. no hints do it yourself.. its very easy

btw.. nice challenge.. researched and learnt a lot.. Thankyou..

Good challenge. For beginners: Whenever you are given executable, you must take a close look at it with proper tools...

I'm really stuck here tho, can u pls provide more hint about proper tool? I used wine but couldn't run it

There is another tool mentioned below, also you should definitely have IDA in your toolkit.

I have no idea

Try to find vulnerability in that app

Oh boy, I solved the challenge now. I saw the vulnerability from the start, but didn't know that syntax existed. Honestly, ChatGPT helped a lot. It gave an example of the attack, and that's exactly it.

I still cannot open that app by wine, can u pls provide more hints?

Use a decompiler like Ghidra to just see the source code.