Can you brute my Javascript? This may stump average joe

[JSProgramIA]

Ok I will give you a hint here...

I will be generating a URL to redirect to. And the URL is based on this algo:

<script language="javascript" type="text/javascript">


function StrRotate(aString){

	 var _l1 = aString;
	_l1.substr(_l1.length - 1) + _l1.substr(0, _l1.length - 1);
	return(_l1.substr(_l1.length - 1) + _l1.substr(0, _l1.length - 1));
	
} 




var li = "1234567890abcdefghijklmnopqrstuvwxyz";		// ENTER YOUR SERIAL NUMBER HERE

if(li.length<30) {

	message = "INVALID SERIAL NUMBER. NOT ENOUGH CHARACTERS.";
	
} else {

		l = 0;
			for (i = 1; i < li.length; i++){
			
				l = l + li.charCodeAt(i);
				
			} // end of for
			
			if (li.charCodeAt(0) - 70 + l % 10 != 6) {
			
				li = "...";
				message = "INVALID SERIAL NUMBER.";
				
			} else {
			
				//-------------------------------------
				// Passed THAT test, now some more pain
				//--------------------------------------
				li = li.substr(1);
				x = "XN69-IWCH7RVPJQF3Y4G8T05A1LB.2OMDEKZSU";
				y = li;
				li = "";
				
				 for (i = 0; i < y.length; i++)
				{
					x = StrRotate(x);
					l = x.indexOf(y.charAt(i));
					if (l < 26)
					{
						li = li + String.fromCharCode(l + 65);
						continue;
					} // end if
					if (l < 36)
					{
						li = li + String.fromCharCode(l + 48 - 26);
						continue;
					} // end if
					li = li + String.fromCharCode(l + 45 - 36);
				} // end of for
				
				li = li.substr(2, Number("0x" + li.substr(0, 2))).toLowerCase();
        		if (li.substr(li.length - 5) == "-bulk"){
        
					message = "VALID SERIAL!!";
		
        		}
			
			}
	
} // End Length Check

alert(message);


</script>

I am wondering if any Guru's could write brute this. Depending on the time it takes for someone to solve this, I will know how secure this is.

( Then of course I will change it a bit )

Any takers?

Giovanni

 

[BabyJeffy]

Unless you are implementing a true one-way transformation, this will always be a weak solution that is open to being broken. Unless you perform a check server-side, this code is nothing but obfuscation.

Are you developing this for a commercial purpose? If so... let me know when you go live so I can come and get access for free

Cheers,
Jeff

[tt]Jeff's Page [/tt][tt]@[/tt][tt] Code Couch

http://www.codecouch.com/jeff/

[/tt]

 

[JSProgramIA]

Point noted.

However, "easily" I don't think so. I have been a programmer for 10 years now, and my bruter was a bit challenging. I would be interested to see yours, and know how long it took.

And sorry, this is only for ordering bulk shower handles, available to only dealers with a valid password (serial).

Giovanni

 

[BabyJeffy]

*darn* - although the limescale build-up on our shower handle could mean I'd find a use for a single handle (dunno about bulk...) *lol*

Regarding the challenge... I have written a brute forcer in the past - and I admit that unravelling the algo is always part of the fun. I never said it would be easy... only that it would be "open to being broken".

I'll probably have a play this weekend at it.

When you are happy with the algo, look into obfuscating it as well... so it's not really obvious how it works... that way we get 2 challenges in 1

Cheers,
Jeff

[tt]Jeff's Page [/tt][tt]@[/tt][tt] Code Couch

http://www.codecouch.com/jeff/

[/tt]

 

[JSProgramIA]

Thanks, I look forward to seeing a solution from someone else. The 3 other co-developers here are stumped, although they are not as skilled as you appear to be.

Good luck, and I sure will obfuscate when I am satisfied it is at least somewhat challenging.

Regards.

 

[BillyRayPreachersSon]

Does the second line in your StrRotate function actually do anything, or is is it just there to put people off the scent? I suspect the latter.

Dan


[tt]Dan's Page [blue]@[/blue] Code Couch

http://www.codecouch.com/dan/

[/tt]

 

[BillyRayPreachersSon]

Here's an odd one for you:

"FAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAB"

it's not valid, but by the same token, it doesn't get flagged as invalid either. Paradox?

Dan

[tt]Dan's Page [blue]@[/blue] Code Couch

http://www.codecouch.com/dan/

[/tt]

 

[JSProgramIA]

run a string through the function. you may be suprised.

 

[BillyRayPreachersSon]

Here are two valid serials I've generated:

F12EZFI9_BillyRayPreachersSonIsTheLeetestHax0rDude_e

F12EZFI9_ABigShoutAndGreetzGoOutToBabyJeffy_a

Dan

[tt]Dan's Page [blue]@[/blue] Code Couch

http://www.codecouch.com/dan/

[/tt]

 

[BillyRayPreachersSon]

run a string through the function. you may be suprised.

I have - which is how I found the second line does nothing. It is redundant.

Dan


[tt]Dan's Page [blue]@[/blue] Code Couch

http://www.codecouch.com/dan/

[/tt]

 

[JSProgramIA]

Unbelievable!!!!!!!!!!!!!!!!!!!!!!!!!!!!

So quickly????????????????!!!!!!!!!!!!!!!!!!

Ok, need to tell the Big Cheese at work his little "idea" is not going to work.


???????????

I find this absouletly amazing.

 

[jemminger]

hmm.. seems StrRotate() does nothing more than move the last character to the first position

could be simplified to

function StrRotate(aString){
return aString.charAt(aString.length - 1) + aString.substring(0, aString.length - 1);
}

-jeff

http://www.jeffemminger.com

try { succeed(); } catch(E) { tryAgain(); } finally { rtfm(); }
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