A friend wrote a little program for me to try and crack. It is basically just a standard password screen that delivers a correct or incorrect response.

The password could be stored in a variable within the application. So I can�t attack from the outside. I could write software that would allow me to crack the password screen using repetitive attempts.

I think all the software is doing is:-

Begin
If edit1:= ('Password' or Maybe Variable1)
then
ShowMesage:='Correct';
else
Showmessage:='incorrect';
End

ps. Thats a simple as I can picture it being.

I don�t want to try and reverse engineer the software. I was wondering if anyone knows any other ways of cracking it, or if they know any currently available software that will force this kind of standard windows password screen, I know of only one claymore Brute forcer and its very unreliable.

VIPER


[This message has been edited by Viper2002 (edited 06-03-2002).]

If this is a windoze program (i.e. an exe) then you can use a hex editor and look for strings contained in the program

If its a unix program a very easy way of finding a string in a binary is by using the 'strings' command.

Either way its pretty much the same idea, looking for strings contained in an exe.

--
cEnsE

Another way (maybe this counts as reverse engineering) would be to use a disassembler to find the point in the program where it decides whether to say correct or incorrect and then use a hex editor to make it always say correct (even when it's not).

im not much of a programer and i have no idea what language that is but let me suggest this

Begin
(99)
If edit1:= ('Password' or Maybe Variable1)
then
print:= 'password' > C:/windows/programfiles/crack/pwd.txt';
else
goto:=(99)
End

i just made up my own language there but i think you get the idea. that looks like pascal, is it? either way the idea is that it is faster to write the possible correct passwords to a text file. i hope you realize that there is a lot more to a cracker than just that.

first off you have to specify how your cracker would read from a list or randomly generate text strings.
then ou have to tell it how to enter the value into the target.
finally you would do something like we just outlined in order to give you the results.

keepin mind the hex editor idea is far simpler but if this is just for fun then go for it. now if this was encryption then it would be far harder because you would have to deal with ciphers, but thats another story.



[This message has been edited by syphon detonator (edited 06-04-2002).]

Is it possible to make a program which logs the name and location any file modified or checked on the system while the program is running? Then you could see if any exterior files were accessed during your attempt. If nothing suspicious shows up, you knnow it's an internal password.

Yes that is possible by taking a snapshot of all your drive contents before running the program, then after and comparing the 2 snapshots. Its not 100% fail proof though.

--
cEnsE

Thanks for all the help guys, I have a much better idea of my options now.

Your right syphon, its more for fun than anything else (I program in Pascal by the way � Delphi 4,6 I also do some Java and visual basic).

So I would like to try and crack the password rather than do anything else (for now anyhow) I have tried to write this kind of software before and had a few problems.

Do any of you know where I can find information on how to write a password cracker of this kind? Or know of a currently available software that will work it?

The main problem I have had in trying to write my own is, once the correct password has been found I don�t know how to make the cracker know it has automatically and stop trying to enter more passwords which because the cracker is controlling the keystokes normally crashes and fucks up the computer. I am not sure if this problem can be overcome because the only piece of other software I have seen that cracks any WIMPI type password screen suffered from the same problem.

VIPER


[This message has been edited by Viper2002 (edited 06-04-2002).]

hmm interesting problem. my best advice is to search asta la vista and the other big security sites for similar programs that come with source code. the best way to figure it out is through example. also try subscribing to bugtraq and windows security, you can ask the people on tht list some questions.