App 17!

Learn to reverse engineer through some common application security methods.
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Re: App 17!

Post by Devoney on Thu Mar 19, 2009 7:03 am
([msg=20166]see Re: App 17![/msg])

I have solved the application. I traced the whole procedure, quiete a big one, in the end I found one spot which made a comparisement. I determined the input of my password by trial and error looking at the comparisement. After 7 tries I determined the password.

Maybe not the way to go, but I solved it :D.

I am wondering what the real algo is behind it all... If I could only take a glance at the source code...
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Re: App 17!

Post by NightQuest on Thu Mar 19, 2009 8:48 am
([msg=20177]see Re: App 17![/msg])

Devoney wrote:I have solved the application. I traced the whole procedure, quite a big one, in the end I found one spot which made a comparisement. I determined the input of my password by trial and error looking at the comparisement. After 7 tries I determined the password.

Maybe not the way to go, but I solved it :D.

I am wondering what the real algo is behind it all... If I could only take a glance at the source code...

that's how many people seem to be solving it ^^
and as for the algorithm, you should be able to read the asm! :P
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Re: App 17!

Post by reddie on Fri Mar 20, 2009 2:10 pm
([msg=20254]see Re: App 17![/msg])

Devoney wrote:I have solved the application. I traced the whole procedure, quiete a big one, in the end I found one spot which made a comparisement. I determined the input of my password by trial and error looking at the comparisement. After 7 tries I determined the password.

Maybe not the way to go, but I solved it :D.

I am wondering what the real algo is behind it all... If I could only take a glance at the source code...


I also managed to get the password by watching the compare, but retrieved the algo afterwards to make a keygen
The algo is in fact quite easy, just watch the memory closely, and you will find out, you'll be suprised how easy it is.

I think someone with a bit extended knowledge of asm can make the program itself easily into the keygen.
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Re: App 17!

Post by acskurucz on Fri Mar 27, 2009 10:06 am
([msg=20690]see Re: App 17![/msg])

that's how many people seem to be solving it ^^
and as for the algorithm, you should be able to read the asm! :P

But if you realize something about the syntax, you can do this mission by using an other method. without the asm. :P
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Re: App 17!

Post by ccb31789 on Sun May 17, 2009 3:18 am
([msg=23839]see Re: App 17![/msg])

Great mission!

-- Sun May 17, 2009 7:03 pm --

So for a little bit of an extra challenge, I re-wrote the program in C, matching your program as closely as I could. :P If anyone wants a binary for os x, I can send you one. :) NightQuest, if you could look at my code and tell me how close I actually am to the original, that'd be cool . . . :D
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Re: App 17!

Post by Xerxes500 on Sun Sep 20, 2009 6:51 pm
([msg=29906]see Re: App 17![/msg])

Thanks NightQuest! This was a really fun challenge that opened me up to the basics of keygenning. It would sure be cool if HTS members collaborated and worked on some more difficult programs... ;)
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Re: App 17!

Post by unterbuchse on Tue Jun 28, 2011 7:52 pm
([msg=59149]see Re: App 17![/msg])

I try to use Olly on this, but i cant get anything. I mean it seems that Olly isn't even working with the exe. Do I need a lower Ring Debugger like Soft Ice?. Or are there some tricks with Olly that i dont know.
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Re: App 17!

Post by st5486 on Sun Sep 04, 2011 10:09 am
([msg=61393]see Re: App 17![/msg])

Hello,

There appears to be a bug with the app, or my username...

I've tried this app using the username "userna" and am able to find a key that works, I have verified this by creating the user, logging in and entering the key into the password box for this level.

But my actual username "st5486" does not allow me to extract the key properly. I used the same method as in the above posts and for my "userna" user but the value in ESI in the check towards the end becomes negative, I think this is due to the difference in ascii values between "t" and "5" - The computation on the username messes up slightly.

Any advice on what to do, short of picking another username? :D
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Re: App 17!

Post by smutley on Thu Nov 17, 2011 1:43 pm
([msg=62956]see Re: App 17![/msg])

Hello,

I have a password that works with the application (i get the Congrats message), but when I enter it into the webpage, it is rejected.

Is there still a problem with the challenge?

cheers
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Re: App 17!

Post by TiMShots on Tue Nov 22, 2011 7:16 pm
([msg=63016]see Re: App 17![/msg])

I'm also having a similar issue as the above post. My password is 23 chars in length and the password field on this website only allows 18 chars.

Seems my password is too long?
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