» Twitter 'onMouseOver' security flaw widely exploited

The Twitter website is being widely exploited by users who have stumbled across a flaw which allows messages to pop-up and third-party websites to open in your browser just by moving your mouse over a link. In a worrying development, messages are also spreading virally exploiting the cross-site-scripting (XSS) vulnerability without the consent of users.
Thousands of Twitter accounts have posted messages exploiting the flaw. Victims include Sarah Brown, wife of the former British Prime Minister.

It appears that in Sarah Brown's case her Twitter page has been messed with in an attempt to redirect visitors to a hardcore porn site based in Japan. That's obviously bad news for her followers - over one million of them.

To Mrs Brown's credit, she has posted a warning on her Twitter page:

don't touch the earlier tweet - this twitter feed has something very odd going on ! Sarah

Here's an example of a Twitter profile which is using the exploit to pop-up a message.


It looks like many users are currently using the flaw for fun and games, but there is obviously the potential for cybercriminals to redirect users to third-party websites containing malicious code, or for spam advertising pop-ups to be displayed.
Here's a quick YouTube video I made demonstrating the exploit live on Twitter:
(Enjoy this video? You can check out more on the SophosLabs YouTube channel and subscribe if you like)
Hopefully Twitter will shut down this loophole as soon as possible - disallowing users to post the onMouseOver JavaScript code, and protecting users whose browsing may be at risk.
Some users are also seemingly deliberately exploiting the loophole to create tweets that contain blocks of colour (known as "rainbow tweets"). Because these messages can hide their true content they might prove too hard for some users to resist clicking on them.

Right now you might be safer using a third-party Twitter client rather than the Twitter.com website.
Update Twitter says that it is aware of the problem, and hopes to roll out a patch soon.

Update 2 Twitter has posted a blog entry going into some detail of what happened, and how it says it has now fixed the problem.
Which means that - if you like - you should be safe to follow me on Twitter at @gcluley to keep up-to-speed on the latest security threats. :) Take care folks.

Posted on September 21st, 2010 by Graham Cluley, Sophos
Filed under: Spam, Video, Web 2.0                                 

The Malware, the SMS, and the Money

from Microsoft Malware Protection Center by mmpc

A threat we call Trojan:MSIL/Fakeinstaller.A has been making the rounds lately. It is a slight deviation from the family of malware threats known as Trojan:Win32/Ransom.
The malware is similar to Trojan:Win32/Ransom, which seizes control of the computer by locking the user's screen and then demanding a passcode from the user. The user receives the passcode only after sending an SMS to a premium number.
This particular sample of Trojan:MSIL/Fakeinstaller.A (SHA1: 5a888391750c0efefe9dfc7dd63ed5b78f603ef9) is not as aggressive, but nonetheless racketeers by ripping some freely distributable application from the Internet and then using that to gain profit.
The malware arrives supposedly as an installer for a program. But when users actually try to install the program, they are prompted to send an SMS to a premium number, from which a reply is sent back with a code to unlock and install the application. While the application doesn’t lock up your desktop, unsuspecting users may still get charged to send the SMS to a premium account.


Contrary to Trojan:Win32/Ransom, which is mostly targeted towards Russian users, Trojan:MSIL/Fakeinstaller.A seems to have been purposely made for users residing in other countries in Europe.