MozillaZine

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.


#17 Re: Bad policy strikes again

by sproctor

Sunday September 15th, 2002 9:37 PM

You are replying to this message

I very much agree. Just seems like utter paranoia to me. Perhaps you don't want to go broadcasting everywhere that you have security problems, but I think it's far worse to try to stifle the knowledge of known problems. People will use Mozilla with or without the security problems. Making them public, I would think, would only allow people to help work on or diagnose them who wouldn't be able to otherwise, or allow people to take precautions to prevent falling victim to these bugs. Look at IE, there's plenty of problems with it. I think we're only better off for knowing them.