Didier Stevens

Tuesday 31 July 2007

F-Secure Reverse Engineering Challenge 2007

Filed under: Reverse Engineering — Didier Stevens @ 19:08

Be ready to compete in the F-Secure Reverse Engineering Challenge (http://www.khallenge.com) this Friday. I expected the challenge to start on Thursday like last year, so now I have a scheduling conflict!

It looks like the challenge is organized like last year: go to the website and download the first challenge. Start the program, and provide the correct password (this is where reversing skills come in handy). You’ll be given an e-mail address in exchange for the correct password (a wrong password yields no e-mail address).


Send an e-mail to the address and you’ll get an URL in reply. Download the second challenge and repeat the process. And finally: download the third challenge and repeat the process.

Don’t forget my tools to help you with this challenge:

Now honestly, I don’t expect Challenger to be of any help, except with a dictionary attack on the first challenge. Last year, the passwords for the second and third challenge were so long that brute-forcing was no option.

Think it’s too difficult for you? Think again, this movie (YouTube) shows how easy the first level of last year’s challenge was, XviD hires here.

YACoSTO, One Year Ago

Filed under: Reverse Engineering — Didier Stevens @ 6:04

One year ago, to the day, I posted YACoSTO. I explained how I reversed a program that “protects” data. This is one of my favorite posts, but it hardly gets any hits. I encourage you to read it, because this time, I focus on reversing the protected data rather than the program itself. You might learn a couple of new and simple techniques.

The binary tools I used for the YACoSTO post can be found here, I published them afterwards.

Contrary to what some of you might think, this is not a “I’m on holiday” post 😦 . We took a short cruise in June. My sister-in-law, a professional wedding film producer, shot this movie (YouTube) during our holiday, hires version here. Absolutely no malware, hacking, revering, … in the movie, just holidaying.

Oh, and BTW, until now, nobody ever asked me what YACoSTO means…

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