version 1.0, 1/10/99
Converted to HTML by Penguin
"pleez, pleez, PLEEZ teach me how to hack a Hotmail Account!!!"
-unidentified IRC user
From here on in you walk alone. Neither little_v OR Black Sun Research Facility AND its members will be responsible for
what you do with the information presented here. Do not use this information to impress your "l33t0_b0rit0" friends. Do
not operate in shower. Objects in article may be closer than they appear.
Note: If you see (x), where x is a number, it means that this term is defined at (x) at the bottom of this article.
Table Of Contents
- What Is This All About?
- What Does It Do?
- How Does It Work?
- What else can I do with this hole in Hotmail's Security?
- Terms Defined
- Some URLs
The purpose of this article is NOT, I repeat, NOT to teach someone how to "hack an email account". It's true purpose is
actually MUCH more devious. The purpose of this and all other articles in the "An Exploit Explained:" series is to teach
readers about various web technologies, and the basics of security and exploiting. I will try to give you a hands-on,
learn as you go type of education in computer security. Sound good??? Then let's get in to it!!
On Wednesday, Sept. 22 1999, yet another bleary day in the life of little v, the following message was sent to my inbox:
Date: Wed Sep 22 1999 10:48:04
Author: Georgi Guninski
Message-ID: <[email protected]>
There is a major security flaw in Hotmail which allows injecting and
This exploit works both on Internet Explorer 5.0 (guess IE 4.x) and
Netscape Communicator 4.x.
does not filter properly
So the following HTML is executed <IMG
enabled automatically loading of images (most users have).
Probably this may be used in other HTML tags.
for example displaying a fake login screen where the user enters his password which
is then stolen.
I don't want to make a scary demonstration, but I am sure it is also
possible to read user's
messages, to send messages from user's name and doing other mischief.
such attacks, but obviously there are holes.
It is much easier to exploit this vulnerability if the user uses
Internet Explorer 5.0.
AFAIK this is not a browser problem, it is Hotmail's problem.
The code is:
first message in your Inbox is from :
Ok, don't puke, I'm going to explain what just happened in a fashion that even your dog can understand.
3. What is this all about?
This important part of this posting to the Bugtraq(1) (http://www.securityfocus.com) mailing list is the actual exploit(2).
The exploit would be:
first message in your Inbox is from :
4. What does it do?
As this exploit, when put into an email message sent to a hotmail user, opens a little box using the "alert()"(3) function in
work on its own. You see, the email also says that you need to use the ASCII(5) code for "C" in the message. If I get out
my handy HTML reference book, I can see that the ASCII code is C. If we substitute this into our little exploit, minus
the "read who the first message in your inbox" part, we get this:
5. How does it work?
Finding out how an exploit works is always the part that makes people a bit spindizzy. If we look at that gibberish we
call code one more time we can see that it uses an <IMG>: tag, which all you who took my HTML tutorial would know is
to display an image onto the page. Because hotmail tries to be the "top dog" webmail provider, they allow you to set
autoloading of images, so the image just shows up on the same page as the mail. When you open a new hotmail
account, this option is already set (hurray!). The conflict happens because your normal browser allows you to put
someone's browser, if the conditions are right. Naturally, people like you and me started exploiting hotmail's allowing
messages by way of filtering(6) (boo! hiss!). So normal guys like you and me had to "inject", or put into other html tags,
combine IMG-injecting with ASCII tags to give you the current exploit.
6. What else can I do with this hole in Hotmail's Security?
this exploit. If you don't, here's a few more snippets of code to get you started:
This code opens a window with Blacksun's main page in it when the hotmail user opens your mail:
Note that the above code could point to any page at all (even one that simulates hotmail's "you have been logged out"
screen. *wink* *wink* HINT HINT ;-) )
This code opens 100 windows with blacksun's main page in it (tee hee! self promotion is good!):
The rest is up to you, my friend. By the way, if Hotmail finds a way to make this exploit null and void, please don't mail
me, as I probably already know. Just keep looking for the next big exploit, and then when you've found it, you may tell
That's all for this exploit, if anyone needs me i'll be on irc.2600.net.
7. Terms Defined
(1) Bugtraq - A mailing list where people publicize holes and exploits in various softwares. I highly suggest that you
subscribe at http://www.securityfocus.com.
(2) Exploit - Webster's dictionary sez: " exploit (eks'ploit') - an act remarkable for brilliance or daring; bold deed". Wow.
Think of that the next time you steal someone's ICQ password.
to the alert() function in it. Note: alert('message goes here')
(5) ASCII - A standard for characters on and beyond the normal keyboard.
8. Some URLs
(2) http://come.to/the-lamer - they have some fake hotmail pages that will make you think you were logged out for some reason and ask you to input your password. They also have some tutorials on how to use these pages, etc' etc' etc'.