I am having a hard time debugging a piece of software.

It appears that the creator of this "crackme" challenge has installed an anti-debugger to kill the process whenever I try to debug.

I need to enumerate the anti-debuggers and work around them. That way I can debug the software and crack the license, thus completing the challenge.

So far I am lost and can't find proper instructions on circumventing this issue.

The crackme can be found here:


I am running Radare2.

radare2 -d ./undebuggable

View picture to see the my error...


I'm getting a Stop Process - SIGNAL 17

man 7 signal

SIGSTOP 17,19,23 - Stop - Stop process

  • 1
    Well, if there's something preventing you from debugging it, then there's static analysis to the rescue. I just had a quick look into the binary and what I noticed is that at the entry point it's using fork already and then both the parent and child use ptrace on themselves. That sounds like an effective anti-debugging trick. – 0xC0000022L Oct 23 '18 at 7:49
  • Interesting... I never experienced anti-debugging tricks like this before--most crackmes I've done thus far are debuggable. It's a great learning experience. I will go off of this and research this further. Thank you. – Kenny's Labotatory Oct 23 '18 at 10:11

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