Seventh Challenge:- Crackme #4: Use a code cave

[XorKing Profile]

Crackme #4: Use a code cave to display the correct password.

Is it correct...?

crackme4done.zip

(82.62 KiB) Downloaded 174 times

[hawaii67 Profile]

My solution, w/o copying to clipboard...

Cracmke4_4.zip

(83.44 KiB) Downloaded 155 times

[them123 Profile]

This was a fun challenge. I managed to figure it out and come up with a similar solution to those posted here!

Thanks for the challenges, tuts, and hard work, Random.

I'm really enjoying the tuts on keygenning and looking forward to more!

[random]

I am trying to make this more than just a "tutorial download site", more of an interactive learning site. So your post means a lot to me

[Saduff Profile Website]

My solution:
http://www.mediafire.com/?l941t7jxffx4870

[random]

XorKing: Congratulations. And the password is copied into the clipboard. Nice going. (Though it does appear that you re-created the entire encryption algorithm. Is that correct? You should not need to do that unless you are making an actual keygen

Saduff: You get extra credit for copying the password in to the clipboard, but unfortunately when you try this it does not display the goodboy

Hawaii67: Same as Saduff

[Saduff Profile Website]

The solution is a self-keygen. It's not expected of a self-keygen for the app itself to be working.
You use the self-keygen to get a key and then use the key with the original binary.
Reason I bypassed all the checks is because I didn't want there to be a need to enter a bogus key for it to work.
And if password is left empty, crackme will always display goodboy. Seemed weird to display the key, followed by a goodboy.

[random]

"...Then, after entering the proper username/password, the target should display the goodboy."

[Saduff Profile Website]

Okay, as you wish:
http://www.mediafire.com/?383f2px2k8zpwh9

You think this is better? I think otherwise.

[hawaii67 Profile]

Saduff, thanks a lot for your solution......I was desperately looking for that clipboard thinggy .....

[random]

BINGO!!!

[robin Profile]

Code: Select all

for (int i = 9; i >= 0; i--) {
      szKey[i] = szUserName[i] ^ 0x9;
   }
   *szUserName = *szUserName ^ 0x9;
   *szKey = *szUserName;

the szKey is passwrod!

[Hanan Profile]

Here is my solution, although it is working as it should when i exit the program i get it crashed (don't know way.)
Great tutorials, Keep up the good work.

Cracmke4final.zip

My Solution

(84.75 KiB) Downloaded 143 times

[manho Profile]

never late to learn

Cracmke4_patch.zip

Should have username. w/o password is ok, code cave
1st click incorrect!
2nd click correct!

(83.43 KiB) Downloaded 74 times