Mozilla Privacy Bug

Saturday September 14th, 2002

Yesterday, ZDNet UK News reported that Mozilla has a privacy flaw involving HTTP referers. The flaw can be exploited using the onUnload JavaScript handler, which is triggered when a visitor leaves a page (for example, by clicking a link or using a bookmark). The problem is that the referer Mozilla sends is the URL of the page that the visitor is going to, not the page that he or she is exiting. This means that a site can discover where you are heading when you leave.

The security bug is present in the latest versions of Mozilla (including 1.0.1, 1.1 and 1.2 Alpha) as well as some Mozilla-based browsers, such as Netscape 6.x, Netscape 7.0, Galeon 1.2.x and Chimera 0.5. At the time of writing, no fix is available. A workaround is to disable JavaScript (Edit > Preferences > Advanced > Scripts & Plugins).

A demonstration of the exploit has been created by security researcher Sven Neuhaus, who posted details of the vulnerability to Bugtraq on Wednesday.

The bug was filed in Bugzilla as bug 145579 on Sunday 19th May, with the more serious onUnload behaviour found on Friday 7th June. The report is currently marked as "Security-Sensitive" and access to it is restricted in line with the Mozilla Security Bugs Policy.

UPDATE! Bug 145579 has now been made public.

ANOTHER UPDATE! A fix has been checked in to the trunk. A patch for the 1.0 branch will follow shortly.

YET ANOTHER UPDATE! A patch has now been checked in to the 1.0 branch.

#16 Bad policy strikes again

by jwb

Sunday September 15th, 2002 9:07 PM

You are replying to this message

Go ahead and flame me again Asa, but the security bug policy is shown AGAIN to be bad and unworkable. The policy of restricting access to security bugs keeps people from knowing about a problem, without promoting a timely fix. In the case of bug 145579, the restriction was used as a whitewash. The bug was reported, the access was restrict, and we got TWO major releases (1.0 and 1.1) without a fix.

The only thing that got us a fix in this case was Bugtraq lighting fires under asses. This is exactly the behavior that I expect from some useless software megacorps, but not from the shining flag-bearer of open development.

Finally, I want to say that is is *immoral* to know about security flaws in software without reporting them to your users. It is doubly bad to intentionally hide the problem without making an effort toward fixing it for over four months.