Hacking Hotmail made easy

Hurry, before they close the hole

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Some bright empiricist from Root-Core has discovered that anyone can log into their Hotmail account and then call messages from any other Hotmail account by crafting a URL with the second account's username and a valid message number.

Finding a valid message number is of course total guesswork, but they all follow a consistent format and always have the same number of digits (i.e., a time stamp), so with the help of a little brute-force progie one can try numerous combinations in the background rather than type them in.

The basic URL for an attack looks like this:

http://pv2fd.pav2.hotmail.msn.com/cgi-bin/saferd? _lang=EN&hm___tg=http%3a%2f%2f64%2e4%2e36%2e250%2fcgi%2dbin%2fgetmsg&hm___qs=%26msg%3dMSGXXXXXXXXX% 2e(X)X%26start%3d1%26len%3d99999999999%26login% 3dUSERNAME%26domain%3dhotmail%2ecom

where USERNAME is the account name, XXXXXXXXX is a nine-digit message number, and (X)X is a second number between zero and (I think) fifty-nine.

(I've inserted spaces in the URL so the page here doesn't grow a mile wide, so be sure to remove them before you play with it.)

Now, let's say you have a Hotmail account called r00tarded@hotmail.com. Just log in, click on any message in your inbox, and then look at the URL. You'll see something like this:

http://lw2fd.hotmail.msn.com/cgi-bin/getmsg? curmbox=F000000001&a=5691b2b44e104176111971aa0fbb1274&m sg=MSG998000947.3&start=197078&len=1060&msgread=1&mfs=182

Copy the URL and log out. Now, log into another of your Hotmail accounts, and commence to play.

The message number for the item you viewed in your r00tarded account is MSG998000947.3 and it needs to be inserted in the attack URL along with the username thus:

http://pv2fd.pav2.hotmail.msn.com/cgi-bin/saferd? _lang=EN&hm___tg=http%3a%2f%2f64%2e4%2e36%2e250%2fcgi% 2dbin%2fgetmsg&hm___qs=%26msg%3dMSG998000947% 2e3%26start%3d1%26len%3d99999999999%26login% 3dr00tarded%26domain%3dhotmail%2ecom

It's necessary that you be logged into another (any other) Hotmail account. Now copy in the attack URL, click 'go' and voila.

You can only read messages; the button links on the page don't work; they'll bounce you back to the account you're working from. But it is a nifty trick, and it is proof of a major hole in Hotmail security.

The hacking danger here is very much limited by the need to guess message numbers, which is slow going. And while there is a handy program for bruting the numbers it's quite slow, trying only about one message page per second in 'fast' mode.

It has a GUI but remains a bit clunky, and also needs to be paused after it brings up the Hotmail login page so you can enter a valid username and password. After two unsuccessful attempts, I got it to work as advertised. It's more a proof-of-concept exercise than a cracking tool -- so enjoy it as such.

And please, I beg you, don't contact me for tech support. I've nothing to do with it. It works; it does take a bit of tweaking; so just give it a whirl and be playful. ®

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