decryption in PHP

Dave101 · #1 29-Mar-2007, 13:21

Here is a program in PHP that has the hidden text. When you run this program it displays "BOOKMARK". Could anyone tell me why is this BOOKMARK being displayed. Like which part of the code has made this or from where the hidden word came?

The program is:

PHP Code:


<?php
  eval(base64_decode("JGZpbGVuYW1lPSRfU0VSVkVSWydTQ1JJUFRfTkFNRSddOw=="));
   $file = basename($filename); 
   $fp = fopen ($file, "r")
      or die("can't open file");
 
   if($fp)
     {
       while (!feof ($fp))
         { 
           $buffer = fgets($fp, 4096);
 
           for ($i=0; $i < strlen($buffer); $i++)
             { 
               if ($buffer[$i] == '?' && $buffer[$i+1] == '>')
                 {
                   $i+=2;
                   $cc = $n = 0;
                   while ($i < strlen($buffer))
                     {
                       while ($buffer[$i] == '\r')$i++;
                       while ($buffer[$i] == '\n')$i++; 
                       $n = ($n << 1) | (ord($buffer[$i])&1); 
                       if (++$cc%8==0)
                         { 
                           print chr($n);
                           $n = 0;
                         } 
                       $i++;
                     }
                 }
             }
         }
       fclose($fp);
     }
 ?>

admin · #2 29-Mar-2007, 17:55

You can echo any variable to see what it's supposed to be storing/doing.

For example, take this line for instance:

PHP Code:


eval(base64_decode("JGZpbGVuYW1lPSRfU0VSVkVSWydTQ1JJUFRfTkFNRSddOw=="));

You can insert a line to that like this:

PHP Code:


eval(base64_decode("JGZpbGVuYW1lPSRfU0VSVkVSWydTQ1JJUFRfTkFNRSddOw=="));
//*
echo base64_decode("JGZpbGVuYW1lPSRfU0VSVkVSWydTQ1JJUFRfTkFNRSddOw==");
//*/

That will reveal that the eval function is being fed:

Code:

$filename=$_SERVER['SCRIPT_NAME'];

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decryption in PHP

Re: decryption in PHP