Firefox Flaw Makes Password Theft Possible

Computerworld reports that a flaw in Firefox’s password management software can allow malicious sites to retrieve password information from users.

For this attack to work, attackers need to be able to create HTML (Hypertext Markup Language) forms on the Web site, something that is allowed on blogging and social networking sites.

The attack was used in a MySpace phishing attack reported in late October. In that attack, users registered a MySpace account named login_home_index_html and used it to host a fake log-in page that exploited the flaw.

This page sent MySpace username and password information to another Web site, and MySpace users who visited the page using Firefox could have easily had their information compromised, said Chapin.

Firefox developers rate this bug critical, according to an entry in the project’s Bugzilla database.

The flaw arises because Firefox’s Password Manager does not perform a thorough enough check when it is deciding whether to send password information, and then does not ensure that password information is being sent to the server that requested it.

In this light, Internet Explorer is more secure than Firefox because it actually checks whether the passwords are being sent to the server that actually requested it. Still, I would think that it’s ultimately up to the user whether his system is compromised or not, since the actual act of submitting form information would rely on user intervention. If you sense something suspicious about a site’s asking for your username and password–and if Firefox has automatically entered information for you–then think twice before hitting the Submit button. It’s always a good idea to double-check the site URL before going ahead with logging in.