hi, firefox does not contain any particular uuid that it would make available to websites. however from your system details it appears that you are using a very outdated version of firefox and a very outdated version of flash which are both affected by many dozens of critical security vulnerabilities which are taken advantage of by every exploit kit out there.

i'm not sure that the normal advice to update firefox to the latest version & update your plugins as soon as possible would work here, since your system might already be heavily compromised...

Hi, here is a more recent version of Firefox. Pardon me for stressing about the core of my question, but it's the very concept of UUID that is not completely clear to me. I can't understand whether the UUID depends on some hardware serial mumber (like a MAC address for example), on the specific installation of the browser, or on both of them. I could observe that, from time to time, I receive a cookie that is either named "UUID" or contains the word "UUID" followed by a long HEX number. Reading here and there on the web, it seems that the UUID is formed by two parts, one that never changes and one that may change: did I understand right? So it seems that UUID is a sort of numberplate, or tag, that one can never change completely. If that's correct, I don't like it at all.

there is no uuid concept in firefox and websites cannot access your mac-address. when they set a "uuid" cookie that will be an arbitrary one - if you clear such a cookie, you will receive a totally different one the next time.

sure, there are certain advanced way of tracking users by fingerprinting their browser (see https://panopticlick.eff.org/ for some information about this) but if you are concerned about your security and privacy there are far more urgent issues with your current setup as i have described in my first answer.

There is only an UUID for crash reports, but as written above there are scripts around the internet to fingerprint the browser. You can remove the cookies from a website to make the website forget about you.

cor-el said

There is only an UUID for crash reports, but as written above there are scripts around the internet to fingerprint the browser. You can remove the cookies from a website to make the website forget about you.

Question: what about fingerprinting if I use a "portable" browser, deleting it completely from the USB stick between two sessions (i.e. copying it to the USB stick from a source folder)? Would that prevent tracking the computer from session to session?...

Hi

I think it is important to echo the point made by philip that you are using outdated, old and possibly insecure copies of Firefox and Flash. Updating both of these (as per the links mentioned in the earlier post) is strongly recommended.

To change a UUID for a Windows based computer, you will need to access the BIOS. Before doing so, I recommend you consult several specialist security or Windows forum who will be able to provide further guidance on this delicate operation and that you back up all your data beforehand.

Fingerprinting is again a specialist topic that the EFF (who produced the Panopticlick service) has further guidance.

I hope this helps. Please update you copy of Firefox and Flash as soon as possible.

Another defense against full 'fingerprinting' of browser is DON'T USE fullscreen... For things like tor browser which is a heavily modified firefox instance fullscreen is not the default for this among other reasons.

I beg you pardon folks, but I'm getting more and more confused... Apart from updating the browser, I mean, the concepts behind UUID and fingerprinting remain quite foggy to me.

Philipp wrote: "there is no UUID concept in firefox". Seburo wrote: "To change a UUID for a Windows based computer, you will need to access the BIOS."

So, if I understood it right, there is an UUID stored somewhere in the system (where?), but Firefox would not make it visible outside? And what "determines" the UUID? Does it depend on some random number generated at BIOS or operating system installation/first run?

[confused mode ON]

Hi

To answer your questions:

Philipp is spot on in saying that there is no Unique User ID number in your copy of Firefox.

Your computer may have a UUID which is stored in the BIOS. You cannot see it in Firefox. You may be able to see it in your operating system, but that is outside of the scope of this forum to comment on - you will be able to get much better support on this matter from a Windows XP support forum.

Likewise with viewing and changing information in the BIOS. This is well beyond what we support here and is something that I would recommend studying several sources of information (and doing a full backup and making sure you have recovery media to hand) before attempting.

If you have a support question about Firefox, please ask and we will do our best to help but I think that the questions you are asking are probably best answered in other more specialist forums

Thank you very much! Indeed, I didn't want to go off-topic with my question, but as I said, I wasn't sure if the UUID is something Firefox-related, computer- related, none, or both. :o)