Message-ID: <BANLkTinAn+LSujxfHoeF7Kr1s+zhdx51Jg@mail.gmail.com>
Date: Wed, 13 Apr 2011 16:07:40 +0100
From: Cal Leeming <cal@...whisper.co.uk>
To: Christian Sciberras <uuf6429@...il.com>
Cc: full-disclosure@...ts.grok.org.uk
Subject: Re: guess what this does..

That's been happening for years tho lol.

In this case, the botters were trying to use the join pages as a cc checker
lol.

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/
>>>>
>>>
>>>
>>
>

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