Cracking Outkast3k's Crackme #1

Outkast3k's Crackme #1 Written by Phueghy

Introduction

I thought it was time again to do some cracking and produce a new tut, so here it is:
How to crack Outkast3k's Crackme (this time we only fish a valid serial; keygen might
follow later. So letz get it on!

Tools required

SoftICE (any version)

Target's URL

http://crackmes.cjb.net

Essay

So letz start cracking this thing. hope you have Sice enabled. fire up the crackme. we see 2 sections: the first needs us to enter a serial so that the button for checking the 2nd part gets enabled. right, enter some serial (i use 39143214), goto softice (ctrl+d) and type: bpx hmemcpy. F5 and press the 'Enable'-Button. we break in sice. press f11 once and start tracing with f10 until you come to this code:

017F:0042DD1A	mov eax, [ebp-04]

at this point, type d eax. it shows our fake serial! Ahh! trace on with F10 to this point:

017F:0042DD21	mov eax, [ebx+1FC]

once again: d eax. what is that? hey, the serial we need to enter really. disable your breakpoints, and enter this serial: 001182102. great, the 'Test-It'-button gets enabled. so we enter some new info (i use Phueghy as name and 39143214 for the serial), enable the breakpoint on hmemcpy again and press the button. it breaks. but as this check only gets our name, we press F5 and break again in hmemcpy, when it gets the serial. Once F11 and now trace with F10 along until you find this code:

017F:0042DC48	mov eax, [ebp-04]

As we already know, this moves our serial to eax (check it with d eax). trace on to

017F:0042DC5A	mov edx, [ebp-08]

this moves the real serial into edx, which is compared to our entered (resting in eax) in the following call. the conditional jump afterwards decides whether to show the good-/bad-boy message. so at that point just type d edx to see the real serial in the data window. clear your breakpoints and leave sice. enter the information and it says "registered". Great, another crackme cracked. Here's my info, if you wanna know: Enable serial: 001182102
Name: Phueghy
Serial#: 65F92424
for a keygen i have not the time now, perhaps it follows later..

Final Notes

This crackme helped me improving my skills on cracking with softice and the hmemcpy function. so if you aren't that fit on this topic, you should try it on your own.

My Greetz Goes to:

Laokoon
tnHuan and every member of Tres2k
everyone in #cracking4newbies
and everyone who i forgot ;-)

When ever there is a door,
there is an entrance.
And behind an entrance can no secret hide,
when a cracker takes his knowledge for a ride
McCodEMaN

ObDuh

As this is a tut on cracking a crackme, all you have to accomplish is that Outkast3k wrote it!

My Greetz Goes to:

When ever there is a door, there is an entrance. And behind an entrance can no secret hide, when a cracker takes his knowledge for a ride McCodEMaN

When ever there is a door,
there is an entrance.
And behind an entrance can no secret hide,
when a cracker takes his knowledge for a ride
McCodEMaN