Mac Reversing

Today I decided to give a look at Challenge #3 since it promised nasty tricks. Now that looks like a challenge and I love challenges! If you think this is a spoiler then stop reading and come back in a week or so. There is no solution for the challenge; I’m more interested in the “nasty” trick used and why the tools are failing. And I don’t need the Challenge itself to analyse this behavior since I can reproduce it with own code....

The MBA is over and I’m enjoying my vacations to clear stuff from the Todo list, to read books, to play some games and to do other stuff. Today the MacSerialJunkies contest started and I decided to give it a go. It’s a very simple crackme with a small twist where you have to bruteforce a MD5 string. I had reversed the serial routine and was starting the bruteforce without thinking much about it (first attempts were by searching online MD5 hashes databases for the correspondent plaintext but no such luck)....

Hello, I have just added a page to collect crackmes for OS X. I have added the ones that I already had and some recommended from user comments. Since corruptfire.com seems down I cannot retrieve the other ones they had. If you have more crackmes please mail them to me so I can add them to the page. It would be nice to start having more crackmes developed for OS X....

I have been thinking about this and how to get this blog back to life. My free time has been almost zero but I miss the motivation to put my brain to tinker and create new things to publish, because reversing and everything around it sometimes is a great relaxing activity for me. The last couple of days I had to revisit one of my favourite books ever, where it is written that “DO NOT COVET YOUR IDEAS: Give away everything you know, and more will come back to you....

I just finished my brief analysis on this protection and I have a very macro view about it and how to break it. If my gut is correct (if you have read Blink! you will trust your gut most of the times, if not go read it since it’s a great book) I can decrypt and run any game so I will not publish any detailed information about it. The protection is based on a keyfile that is sent to you after you register online....