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.

#18 Re: Bad policy strikes again

by kristen

Sunday September 15th, 2002 10:34 PM

You are replying to this message

A lot of it simply has to do with all of the spouting off that many of those within the inner recesses of the Mozilla circle have done over the past several years. Boasting and bragging about the security of Mozilla (an unfinished and hardly used product during the whole time) in concert with the bashing of vulnerabilities reported in IE: A product with extremely heavy usage that is close under the microscope by all sorts of individuals and groups (good and evil).

Between Mozilla 1.0 and Mozilla 1.0.1 there were 25 security holes discovered (by the mozilla community alone) and now this: An issue known now for quite some time.

So, in a way you can't blame them for being so hush hush. Most are relatively young and don't know any better. Of course, they'll try to come up with excuses and rationalizations like they always do (or try to I should say).

If I were them, I'd be feeling pretty embarassed and stupid, too, to say the very least.