Date: Wed, 13 Apr 2011 19:10:40 +0100
From: Cal Leeming <cal@...whisper.co.uk>
To: Chris M <chris@...lroute.net>
Cc: full-disclosure@...ts.grok.org.uk
Subject: Re: guess what this does..

Absolutely nothing. It really is only meant to stop "stupid bots", which for
us, was good enough at the time ;p

On Wed, Apr 13, 2011 at 7:07 PM, Chris M <chris@...lroute.net> wrote:

> How does all of this stop someone feeding the obfuscated code into jsunpack
> and reloading it into a bot application with an inbuilt browser object and
> just following links etc?
>
>
> On Wed, Apr 13, 2011 at 3:50 PM, Christian Sciberras <uuf6429@...il.com>wrote:
>
>> Is it me or are spammers recruiting more script kiddies as of late?
>> Not much of a big deal considering their numbers are on the rise...*ahem*
>> anonymous *ahem*.
>>
>> Chris.
>>
>>
>>
>>
>> On Wed, Apr 13, 2011 at 4:47 PM, Cal Leeming <cal@...whisper.co.uk>wrote:
>>
>>> Well, the problem was the person(s) running the bots kept bypassing the
>>> simple protections such as these. Although it isn't 100% fool proof, it does
>>> make things *extremely* difficult for the person(s) with the bots, so much
>>> so, that they usually give up, unless they have specifically targeted you
>>> for some reason.
>>>
>>> So, instead we created hundreds of these little JS chunks, all with
>>> different lookup tables applied, and cycled them on an hourly basis. It
>>> meant if they wanted to continuously bot the service, they would have to de
>>> obfuscate the protection code, or find a mathmatical/bruteforce attack that
>>> would generate the seedkey for them. It would either involve manual
>>> intervention or code modification on the bot to make it work.. I'd
>>> have preferred to have added captcha, but there was a reasonable explanation
>>> as to why the client didn't want it.
>>>
>>> Either way, once we put this in, they gave up pretty quickly lol.
>>>
>>>
>>> On Wed, Apr 13, 2011 at 3:29 PM, Christian Sciberras <uuf6429@...il.com>wrote:
>>>
>>>> Cal /Ryan,
>>>>
>>>> I'm not sure what you're trying to achieve.
>>>> If we're talking about absolutely stupid bots, the following easily
>>>> defeats them:
>>>>     <form>
>>>>         <stuff/>
>>>>         <script type=text/javascript>document.write('<input
>>>> type="hidden" name="access" value="code"/>');</script>
>>>>     <form>
>>>>
>>>> I suppose you could obfuscate it all if you wanted to cater for script
>>>> kiddies.
>>>> But considering this is very weak protection (as opposed to proper
>>>> captcha), I'm not sure if it's even worthwhile.
>>>> One of the ways I can see this work is against automated, "JS-ignorant",
>>>> MITM systems.
>>>>
>>>> As indeed is true, you should never trust the end user.
>>>> But in a MITM scenario, the user we're not trusting is the one
>>>> conducting the attack, not the other.
>>>>
>>>> Chris.
>>>>
>>>>
>>>>
>>>> On Wed, Apr 13, 2011 at 1:07 PM, Cal Leeming <cal@...whisper.co.uk>wrote:
>>>>
>>>>> Lol, I've just realised something.. I didn't include the seed key
>>>>> variable itself, so this code would have been pretty much useless on it own
>>>>> *DOH*.
>>>>>
>>>>> So, here's something else a bit tasty.. this is the server side code
>>>>> used to check and create the seedkey itself (secret lookup table has been
>>>>> changed obv.).
>>>>>
>>>>> This code allows seedkeys to be generated from epoch time. Now,
>>>>> cryptographically I don't know how "sane" this is, but I'm fairly sure that
>>>>> if the lookup table contained large integers it would become almost
>>>>> impossible to do a pattern based brute force. I actually had quite a lot of
>>>>> fun trying to break my own code. :D
>>>>>
>>>>> PS) you have been awarded 1 internets.
>>>>>
>>>>>
>>>>>     function get_valid_keys() {
>>>>>         // Create key store
>>>>>         $_s = array();
>>>>>
>>>>>         // Create valid key ranges (+900 seconds)
>>>>>         for($x=300;$x>=900;$x+=300):
>>>>>             $_s[] = $this->create_key($offset=$x);
>>>>>         endfor;
>>>>>
>>>>>         // Create valid key ranges (-900 seconds)
>>>>>         for($x=300;$x>=-900;$x-=300):
>>>>>             $_s[] = $this->create_key($offset=$x);
>>>>>         endfor;
>>>>>
>>>>>         $_s[] = $this->create_key();
>>>>>
>>>>>         return $_s;
>>>>>     }
>>>>>
>>>>>     function create_packed_key() {
>>>>>         // Create a new valid key
>>>>>         $key = $this->create_key();
>>>>>
>>>>>         // Now generate the packed key
>>>>>         $k = array();
>>>>>         // Now convert it into an array
>>>>>         for($x=0;$x<strlen($key);$x++):
>>>>>             $_v = unpack("H*", $key[$x]);
>>>>>             $k[]='\x'.$_v[1];
>>>>>         endfor;
>>>>>
>>>>>         // Okay, here is your brand new shiney key, sir :)
>>>>>         $m = '"'.implode('","', $k).'"';
>>>>>         $m = strrev($m);
>>>>>         $_m = array();
>>>>>         for($x=0;$x<strlen($m);$x++):
>>>>>             $_m[]=$m[$x];
>>>>>         endfor;
>>>>>         return json_encode(implode("ZPAK", $_m));
>>>>>     }
>>>>>
>>>>>     function create_key($offset=0) {
>>>>>         // Secret key table, used to mix up the seed
>>>>>         $enc = array(
>>>>>                 0       =>       "67892",
>>>>>                 1       =>       "3953",
>>>>>                 2       =>       "49474",
>>>>>                 3       =>       "494755",
>>>>>                 4       =>       "30585",
>>>>>                 5       =>       "30582",
>>>>>                 6       =>       "20485",
>>>>>                 7       =>       "20486",
>>>>>                 8       =>       "97294",
>>>>>                 9       =>       "10284"
>>>>>         );
>>>>>
>>>>>         // Generate new seed
>>>>>         $time = time();
>>>>>         if ($offset):
>>>>>             $time=$time+$offset;
>>>>>         endif;
>>>>>         $c=(int)($time/$this->_security_key_refresh);
>>>>>         $_c = "$c";
>>>>>
>>>>>         // Extract the last 5 digits of the number
>>>>>         $char1 = substr($_c, strlen($c)-1, 1);
>>>>>         $char2 = substr($_c, strlen($c)-2, 1);
>>>>>         $char3 = substr($_c, strlen($c)-3, 1);
>>>>>         $char4 = substr($_c, strlen($c)-4, 1);
>>>>>         $char5 = substr($_c, strlen($c)-5, 1);
>>>>>
>>>>>         // Lookup the modifier from the secret key table
>>>>>         $mt1 = $enc[$char1];
>>>>>         $mt2 = $enc[$char2];
>>>>>         $mt3 = $enc[$char3];
>>>>>         $mt4 = $enc[$char4];
>>>>>         $mt5 = $enc[$char5];
>>>>>
>>>>>         // Generate a new key, based on the modifiers
>>>>>         $key = round((($c+$mt1) + ($c+$mt2) + ($c+$mt3) + ($c+$mt4) +
>>>>> ($c+$mt5))/256);
>>>>>         $key = "$key";
>>>>>         return $key;
>>>>>     }
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Apr 13, 2011 at 3:56 AM, Ryan Sears <rdsears@....edu> wrote:
>>>>>
>>>>>> Me thinks I may have it right (mostly)...
>>>>>>
>>>>>> It seems to be some jquery to append a hidden input element to the
>>>>>> "theform" id (presumably a form on the page ;) ) called "seedkey", and has a
>>>>>> value of whatever t is evaluated to (which I'm still stuck on as I don't
>>>>>> know jquery much at all, so I can't figure out the s[] array, but I know it
>>>>>> has something to do with the bracket notation...).
>>>>>>
>>>>>> =================================================
>>>>>> += Orig =+
>>>>>> $(function () {
>>>>>>        var _0xafd3 = ["\x74\x20\x3D\x20\x22", "", "\x6A\x6F\x69\x6E",
>>>>>> "\x72\x65\x76\x65\x72\x73\x65", "\x73\x70\x6C\x69\x74",
>>>>>> "\x72\x65\x70\x6C\x61\x63\x65", "\x22"];
>>>>>>
>>>>>>        eval(_0xafd3[0] + s[_0xafd3[5]](/ZPAK/gi,
>>>>>> _0xafd3[1])[_0xafd3[5]](/\",\"/gi, _0xafd3[1])[_0xafd3[5]](/\"/gi,
>>>>>> _0xafd3[1])[_0xafd3[4]](_0xafd3[1])[_0xafd3[3]]()[_0xafd3[2]](_0xafd3[1]) +
>>>>>> _0xafd3[6]);
>>>>>>        var _0x5bfa = ["\x3C\x69\x6E\x70\x75\x74\x20\x2F\x3E",
>>>>>> "\x74\x79\x70\x65", "\x68\x69\x64\x64\x65\x6E", "\x61\x74\x74\x72",
>>>>>> "\x6E\x61\x6D\x65", "\x73\x65\x65\x64\x6B\x65\x79", "\x76\x61\x6C\x75\x65",
>>>>>> "\x61\x70\x70\x65\x6E\x64", "\x23\x74\x68\x65\x66\x6F\x72\x6D"];
>>>>>>        _n = $(_0x5bfa[0]);
>>>>>>        _n[_0x5bfa[3]](_0x5bfa[1], _0x5bfa[2]);
>>>>>>        _n[_0x5bfa[3]](_0x5bfa[4], _0x5bfa[5]);
>>>>>>        _n[_0x5bfa[3]](_0x5bfa[6], t);
>>>>>>        $(_0x5bfa[8])[_0x5bfa[7]](_n);
>>>>>> });
>>>>>>
>>>>>> += De-obfuscated =+
>>>>>> $(function () {
>>>>>>        var _0xafd3 = ['t = "', '', 'join', 'reverse', 'split',
>>>>>> 'replace', '"'];
>>>>>>        var _0x5bfa = ['<input />', 'type', 'hidden', 'attr', 'name',
>>>>>> 'seedkey', 'value', 'append', '#theform'];
>>>>>>
>>>>>>        eval('t = "' + s['replace'](/ZPAK/gi, '')['replace'](/\",\"/gi,
>>>>>> '')['replace'](/\"/gi, '')['split']('')['reverse']()['join']('') + '"');
>>>>>>
>>>>>>        _n = $('<input />');
>>>>>>        _n['attr']('type', 'hidden');
>>>>>>        _n['attr']('name', 'seedkey');
>>>>>>        _n['attr']('value', t);
>>>>>>        $('#theform')['append'](_n);
>>>>>> });
>>>>>>
>>>>>> =================================================
>>>>>>
>>>>>> Fun stuffs. I can haz a internetz? :-P
>>>>>>
>>>>>> Ryan
>>>>>>
>>>>>>
>>>>>> ----- Original Message -----
>>>>>> From: "Cal Leeming" <cal@...whisper.co.uk>
>>>>>> To: full-disclosure@...ts.grok.org.uk
>>>>>> Sent: Tuesday, April 12, 2011 5:28:22 PM GMT -05:00 US/Canada Eastern
>>>>>> Subject: [Full-disclosure] guess what this does..
>>>>>>
>>>>>>    $(function() {
>>>>>>    var
>>>>>>
>>>>>> _0xafd3=["\x74\x20\x3D\x20\x22","","\x6A\x6F\x69\x6E","\x72\x65\x76\x65\x72\x73\x65","\x73\x70\x6C\x69\x74","\x72\x65\x70\x6C\x61\x63\x65","\x22"];eval(_0xafd3[0]+s[_0xafd3[5]](/ZPAK/gi,_0xafd3[1])[_0xafd3[5]](/\",\"/gi,_0xafd3[1])[_0xafd3[5]](/\"/gi,_0xafd3[1])[_0xafd3[4]](_0xafd3[1])[_0xafd3[3]]()[_0xafd3[2]](_0xafd3[1])+_0xafd3[6]);
>>>>>>    var
>>>>>>
>>>>>> _0x5bfa=["\x3C\x69\x6E\x70\x75\x74\x20\x2F\x3E","\x74\x79\x70\x65","\x68\x69\x64\x64\x65\x6E","\x61\x74\x74\x72","\x6E\x61\x6D\x65","\x73\x65\x65\x64\x6B\x65\x79","\x76\x61\x6C\x75\x65","\x61\x70\x70\x65\x6E\x64","\x23\x74\x68\x65\x66\x6F\x72\x6D"];_n=$(_0x5bfa[0]);_n[_0x5bfa[3]](_0x5bfa[1],_0x5bfa[2]);_n[_0x5bfa[3]](_0x5bfa[4],_0x5bfa[5]);_n[_0x5bfa[3]](_0x5bfa[6],t);$(_0x5bfa[8])[_0x5bfa[7]](_n);
>>>>>>    });
>>>>>>
>>>>>> enjoy ;p
>>>>>>
>>>>>> ps) yes I obfuscated this, and no it doesn't contain any nasties.
>>>>>>
>>>>>> _______________________________________________
>>>>>> Full-Disclosure - We believe in it.
>>>>>> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
>>>>>> Hosted and sponsored by Secunia - http://secunia.com/
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Full-Disclosure - We believe in it.
>>>>> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
>>>>> Hosted and sponsored by Secunia - http://secunia.com/
>>>>>
>>>>
>>>>
>>>
>>
>> _______________________________________________
>> Full-Disclosure - We believe in it.
>> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
>> Hosted and sponsored by Secunia - http://secunia.com/
>>
>
>
>
> --
>  I’m a hot-wired, heat seeking, warm-hearted cool customer, voice activated
> and bio-degradable. I interface with my database, my database is in
> cyberspace, so I’m interactive, I’m hyperactive and from time to time I’m
> radioactive.
>

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