Reverse Engineering w/GDB and Ghidra! | picoCTF 2022 #08 "Keygenme"

[@jasonturley]

Join us on Discord! discord.gg/v2BVAUyj3P

[@theadorelogon112]

Nice demo! GDB is so sweet. Radare has always been my goto for reversing but I'm trying to experiment with Ghidra so a straight example like this was awesome. Also, thanks for not being obnoxious. I'll gently place a like and subscribe on this channel.

[@jasonturley]

Thank you! I’ve played with Radare a few times, but I always revert back to GDB lol. Best of luck with Ghidra!

[@aurinator]

Renaming things to make sense of the code flow was common, even back in the days with SoftICE before you had a GUI. Also though, rather than going into that function and Reversing it, you could just set its return value to the one you want without even messing with the logic in the function it enters.

[@Meodoc]

Thanks! I have never used gdb (or ghidra) before, and with your help I managed to do my first reverse-engineering assignment for my university! :)

[@jasonturley]

That’s awesome! Great job!

[@womacko]

Your videos are totally underrated. This is pure gold for getting started. Thanks for the walkthrough. Stumbled across your channel when looking for "reverse engineering assembly" videos :) Please keep it up and keep uploading. Following!

[@jasonturley]

That means the world to me! Thank you so much!

[@kromaki131]

Awesome video. I was looking for Ghidra introduction video because I'm new to it and then found yours. I didn't expect to have a great introduction to gdb too! It's not only helpful but also motivative. Thank you.

[@jasonturley]

Thank you! Glad I could help and best of luck with reverse engineering!

[@PerJensen-k9r]

I'm a complete noob when it comes to RE, but I understood most of this. Good job!

[@jasonturley]

Thank you, I’m glad it helped! I’m no expert on reverse engineering but it’s fun learning it

[@skrillyvito4232]

This was super helpful man thanks a lot

[@minhkhoavo5807]

How can you double click 18:19, I can not select to coppy it. And at 19:15 when I scroll down to the stack storing the 8 units, It don't same you.

[@jasonturley]

Great question. I pressed the shift key in order to select the text. GDB TUI mode doesn’t directly support copy/paste, but you can bypass it with the shift key. Are you saying you see something different at 19:15? If so, what do you see?

[@rrkatamakata7874]

Do you have any guides for learning reverse engineering. The tools that you use and or the paths tat you recommend

[@jasonturley]

I made a video on this a while back. Admittedly, I think it needs to be remade with more info, but it should be a good starting point: kzbin.info/www/bejne/qnyqiohrrLZ2iaMsi=OM167_KG4Nx4ZfS0 I also recommend the KZbin channel LiveOverflow.

[@nyxon_x]

Hello, can i ask you why you can't find these values that the executable pushes onto the stack via Ghidra and you have to execute it via GBD and print them before returning? Where are these values coming from if they are not hardcoded somewhere? Are they obfuscated? --edit watching it again i see the MD5 uses the flag_pieces, which are hardcoded values, so theoretically you can reproduce this section of code and find the rest of the flag without GDB? I guess GDB is faster in this case, but i was wondering if there is something more i am missing.

[@jasonturley]

Hello! I’m sure you can find the flag entirely in Ghidra (or any other disassembler or decompiler) without having to use a debugger like GDB. Admittedly, I’m not great with Ghidra and feel more comfortable in GDB.

[@anon1234mouse]

I was also wondering how it set up unique keys for each person (to prevent copying) Unless it creates a unique one per entrant

[@etopowertwon]

I really wish debug in ghidra was not so complicated. It could probably rival x96dbg, which I really really miss in linux, as no amount of gefs make gdb comfy for common operations

[@MouatassimMajhoul]

If not then why not select the arch and mode directly insted of selecting windows executable for .exe files ?

[@VivekKumar-gg6cz]

What shortcut you used at 7:40

[@jasonturley]

I think I did Alt +

[@anthonyramnarain9129]

Great Vid

[@jasonturley]

Thank you!

[@PoliticalPanic]

nice - thx for sharing.

[@jasonturley]

Thanks for watching!

[@axionet_dev]

I was select all variable and retype to char[x] char it worked.

[@jasonturley]

Nice!

[@muhammadziyad3648]

can you do reverse engineering state of survival using ghidra ?

[@jasonturley]

I plan to do more game hacking content in the future, currently I’m focusing on more penetration testing related stuff

[@坂井正樹-g1y]

I really respect you and your hacking skills. Thanks for the video.

[@jasonturley]

Thank you!

[@XnndjehdhkNxndjhds]

Johnson George Jones Matthew Johnson Dorothy

[@MaximusHyde]

well, i made it through 51 seconds of annoying typing sounds, but i couldn't take any more. good job me.

[@jasonturley]

Yea my old mechanical keyboard was pretty annoying. I’m surprised so many people put up with it lol