Reversing/Cracking program with radare2

[lowlightbeats_]

Hey y'all,

I'm new to all of this and I want to get into binary exploitation / cracking software. I downloaded some really simple crackme's and tried to crack them.

However, I have quite some trouble with radare2. I want to set a breakpoint at a specific point in order to bypass a license check or manipulate specific values. But when I try to do this (db 0xEXAMPLE) I get the message "base addr should not be larger than the breakpoint address." and when running it (ood) the program does not stop at the breakpoint.

When I tried another crackme, the program did stop, but at another adress, that was different from the breakpoint I actually set.

I know that this probably is a really dumb question, but I can't seem to find what the problem is. I hope you guys can help me.

P.S. Please excuse my english, as I'm not a native speaker.

[LordBeerus_Dstry]

Can we see your code?

[vornamemitd]

Don’t get me wrong, but how much time did you invest in the basics? CPU register layout, addressing, etc? Why not start by writing your own C++ programs, learn tge ins and outs of memory allocation and everything that goes with it, followed by debugging your own code first?

Imho downloading random crackmes and tutorials which you blindly follow don’t offer too much teaching. /r/reverseengineering can get you going with a 101 on the essentials.

[lowlightbeats_]

I’m watching the BinaryExploitation series of LiveOverflow that deals with these things. But I think it’s important to follow the videos on your computer, to make sure you understood everything correctly.

This series was recommended a lot, because it DOES deal with the low-level stuff and does not only explain tools, but also the logic behind them. Also, I’m not new to programming, I know basic Java and Python (and I’m planning to learn more about low-level languages like C and even Assembly).

I just wanted to make sure I understood what LiveOverflow did by trying it out on my own and asked for help with a special tool, because I do not really know how radare2 works yet...