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.

#51 Re: its already fixed

by kristen

Tuesday September 17th, 2002 6:53 PM

You are replying to this message

That's funny. NS7, Galeon, KMeleon, etc... still seem to suffer from this. In fact, anything based on 1.0 has 25+ exploits. Have the security geniuses at installed your new update system that instantly delivers patches to the trunk to all of the mozilla users systems? As well as the products based on gecko?

What puzzles me is why were any of these exploits found to begin with when for years you and others have been touting how secure Mozilla is? 25 discovered internally between 1.0 and 1.01 alone? That's only a few months time!!!

"Designed bottom up with security as top priority" was the big rant for quite a while. Reality is biting you in the ass and this is just the tip of the iceberg if Mozilla's usage share increases enough for any of the evil doers to give a flying rip about it.