COMMAND
hotmail
SYSTEMS AFFECTED
Hotmail
PROBLEM
Georgi Guninski found yet another Hotmail security hole injecting
JavaScript in IE using "@import url(javascript:...)". Hotmail
allows executing JavaScript code in email messages using "@import
url(javascript:...)", which may compromise user's Hotmail mailbox
when viewed with Internet Explorer.
There is a security flaw in Hotmail which allows injecting and
executing JavaScript code in an email message using the javascript
protocol. This exploit works on Internet Explorer. Hotmail
filters the "javascript:" protocol for security reasons. But the
following JavaScript is executed: "@import url(javascript:...)".
Executing JavaScript when the user opens Hotmail email message
allows for example displaying a fake login screen where the user
enters his password which is then stolen. No need for scary
demonstration, but it is also possible to read user's messages,
to send messages from user's name and doing other mischief. It
is also possible to get the cookie from Hotmail, which is
dangerous. Hotmail deliberately escapes all JavaScript (it can
escape) to prevent such attacks, but obviously there are holes.
The code that must be included in HTML email message is:
<style TYPE="text/css">
@import url(javascript:alert('Javascript is executed'));
</style>
SOLUTION
Workaround: Disable Active Scripting.