Despite the convenience of a cloud-based password management service, a security researcher found a cross-site scripting vulnerability in LastPass that could compromise user account data.
Despite the convenience of a cloud-based password management
service, a security researcher warned that putting passwords in the cloud may
not be the best idea after all.
After the Gawker breach
revealed the number of people
across multiple sites, there was renewed interest in using
password management applications such as KeePass and LastPass.
Instead of writing down all the passwords for each Website
and program on a Post-It or saving it as a text file on the computer, the
services allow users to enter the login credentials and secure them with a
strong master password.
The user logs into the LastPass account and clicks on which
site to log into, and the LastPass browser plug-in handles the actual login
process using the stored credentials. However, there was a cross-site scripting
flaw in LastPass that allowed attackers to see the user's e-mail address,
password reminder information, the list of Websites associated with the user
and login history for each site, said Mike
, a United Kingdom-based security researcher. The login history
included sites logged into, time and dates of the login attempt, and the
originating IP address, he said.
While he didn't achieve "the holy grail" to grab passwords,
"I'm convinced it can be done," he said.
Cardwell notified LastPass of the vulnerability, which fixed
the flaw within three hours, according to the LastPass
. The problem was "with our testing procedure for this particular
case," the company said. While "disappointed" at missing the case, the company
was confident the resulting fixes will "lead to an even stronger product in the
The company claimed no one has successfully exploited the
flaw "beyond the person who found it," and no client data was impacted. The flaw
could have been exploited only if the user visited a malicious site set up to
exploit the flaw while still logged into LastPass, the company wrote.
LastPass customers should "still be very concerned,"
Cardwell said. "I believe this is ultimately a problem with their architecture
and something which could easily happen again in future," he said.
The company addressed some of Cardwell's concerns, such as
implementing HSTS (HTTP Strict Transport Security) protocol to ensure
Chrome and Firefox
will maintain the SSL connection as long as the user is on a LastPass
Without HSTS, it was possible for a man-in-the-middle attack to create
lastpass.com page and trick the browser into fetching it by using an
LastPass was implementing "something very similar" to
CSP (Content Security Policy), the company said. Developed by Mozilla, CSP
allows Web designers and administrators to control how content is displayed on the
site. CSP is a "big step forward" in defending against this kind of attack,
according to the company.
The company also implemented X Frame Options, which would
make an attack like this more difficult to exploit as "it makes it impossible"
for the LastPass pages to be embedded in another page using an iFrame.
Despite having closed the security hole, concerned users can
stay safe by logging out of LastPass before heading over to a site with
questionable or adult-related content, LastPass suggested.
"Perhaps it's just inherently dangerous to outsource your
password management to a third party," Cardwell said.