A new attack technique takes advantage of open browser tabs to launch phishing sites without the user's knowledge. The attack can be carried out in Firefox, Internet Explorer and other major browsers.
New security research is shining a light on an attack technique that can be
used to trick users into entering their personal information on phishing
attack, dubbed tabnapping,
was uncovered by Aza Raskin, creative lead for
Mozilla Firefox, and affects all the major browsers on Windows
and Mac OS X.
Raskin's proof-of-concept attack takes advantage of users who keep multiple
tabs open. If the user visits a malicious site or one that has been
compromised, the attacker can silently change the contents and label of an
open, inactive tab to resemble the log-in screen of another site, such as
Raskin demonstrated the attack on his blog. If visitors open another tab and
then go back to the blog, they will see the blog page has changed to a fake
Gmail log-in screen.
"Using my CSS
you can detect which site a visitor uses and then attack that
site (although this is no
in Firefox betas)," Raskin wrote. "For example,
you can detect if a visitor is a Facebook user, Citibank user, Twitter user,
etc., and then switch the page to the appropriate log-in screen and favicon on
"Even more deviously, there are various methods [one can use] to know
whether a user is currently logged into a service. These methods range from
timing attacks on image loads, to seeing where errors occur
when you load an HTML Web page in a script tag ... You can make this attack
even more effective by changing the copy: Instead of having just a log-in
screen, you can mention that the session has timed out and the user needs to
reauthenticate. This happens often on bank Websites, which makes them even more
susceptible to this kind of attack."
Jerry Bryant, group manager for security response communications at
Microsoft, said users should always check to make sure the Lock icon is present
in the address bar before entering personal information on any Website, and
check that the URL of the site is correct. Internet Explorer 8's
SmartScreen filter, which offers some protection against suspected
and known phishing sites, can help mitigate the attack, he added.
Raskin indicated the Firefox Account Manager Mozilla is working on for the
next version of the browser mitigates the attack.
"User names and passwords are not a secure method of doing
authentication; it's time for the browser to take a more active role in being
your smart user agent; one that knows who you are and keeps your identity,
information and credentials safe," he wrote.