- I can't click on links or hit reload after I toggle Tor! Why?
- I can't view videos on YouTube and other flash-based sites. Why?
- Torbutton sure seems to do a lot of things, some of which I find annoying. Can't I just use the old version?
- My browser is in some weird state where nothing works right!
- When I use Tor, Firefox is no longer filling in logins/search boxes for me. Why?
- What about Thunderbird support? I see a page, but it is the wrong version?
- Which Firefox extensions should I avoid using?
- Which Firefox extensions do you recommend?
- Are there any other issues I should be concerned about?
YouTube and similar sites require third party browser plugins such as Flash. Plugins operate independently from Firefox and can perform activity on your computer that ruins your anonymity. This includes but is not limited to: completely disregarding proxy settings, querying your local IP address, and storing their own cookies. It is possible to use a LiveCD solution such as or The Amnesic Incognito Live System that creates a secure, transparent proxy to protect you from proxy bypass, however issues with local IP address discovery and Flash cookies still remain.
The Tor Browser Bundle does not work with Flash or other plugins by design. If you wish to run these plugins over Tor, you need to install Tor and configure your own instance of Firefox.Torbutton sure seems to do a lot of things, some of which I find annoying. Can't I just use the old version?
No. Use of the old version, or any other vanilla proxy changer (including FoxyProxy -- see below) without Torbutton is actively discouraged. Seriously. Using a vanilla proxy switcher by itself is so insecure that you are not only just wasting your time, you are also actually endangering yourself. Simply do not use Tor and you will have the same (and in some cases, better) security. For more information on the types of attacks you are exposed to with a "homegrown" solution, please see The Torbutton Adversary Model, in particular the Adversary Capabilities - Attacks subsection. If there are any specific Torbutton behaviors that you do not like, please file a bug on the bug tracker. Most of Torbutton's security features can also be disabled via its preferences, if you think you have your own protection for those specific cases.My browser is in some weird state where nothing works right!
Try to disable Tor by clicking on the button, and then open a new window. If that doesn't fix the issue, go to the preferences page and hit 'Restore Defaults'. This should reset the extension and Firefox to a known good configuration. If you can manage to reproduce whatever issue gets your Firefox wedged, please file details at the bug tracker.When I use Tor, Firefox is no longer filling in logins/search boxes for me. Why?
Currently, this is tied to the "Block history writes during Tor" setting. If you have enabled that setting, all formfill functionality (both saving and reading) is disabled. If this bothers you, you can uncheck that option, but both history and forms will be saved. To prevent history disclosure attacks via Non-Tor usage, it is recommended you disable Non-Tor history reads if you allow history writing during Tor.What about Thunderbird support? I see a page, but it is the wrong version?
This is a tough one. There are thousands of Firefox extensions: making a complete list of ones that are bad for anonymity is near impossible. However, here are a few examples that should get you started as to what sorts of behavior are dangerous.
- StumbleUpon, et al
These extensions will send all sorts of information about the websites you visit to the stumbleupon servers, and correlate this information with a unique identifier. This is obviously terrible for your anonymity. More generally, any sort of extension that requires registration, or even extensions that provide information about websites you visit should be suspect.
While FoxyProxy is a nice idea in theory, in practice it is impossible to configure securely for Tor usage without Torbutton. Like all vanilla third party proxy plugins, the main risks are plugin leakage and history disclosure, followed closely by cookie theft by exit nodes and tracking by adservers (see the Torbutton Adversary Model for more information). However, with Torbutton installed in tandem and always enabled, it is possible to configure FoxyProxy securely (though it is tricky). Since FoxyProxy's 'Patterns' mode only applies to specific urls, and not to an entire tab, setting FoxyProxy to only send specific sites through Tor will still allow adservers (whose hosts don't match your filters) to learn your real IP. Worse, when sites use offsite logging services such as Google Analytics, you will still end up in their logs with your real IP. Malicious exit nodes can also cooperate with sites to inject images into pages that bypass your filters. Setting FoxyProxy to only send certain URLs via Non-Tor is much more secure in this regard, but be very careful with the filters you allow. For example, something as simple as allowing *google* to go via Non-Tor will still cause you to end up in all the logs of all websites that use Google Analytics! See this question on the FoxyProxy FAQ for more information.
Mentioned above, this extension allows more fine-grained referrer spoofing than Torbutton currently provides. It should break less sites than Torbutton's referrer spoofing option.
If you use Tor excessively, and rarely disable it, you probably want to install this extension to minimize the ability of sites to store long term identifiers in your cache. This extension applies same origin policy to the cache, so that elements are retrieved from the cache only if they are fetched from a document in the same origin domain as the cached element.
Better Privacy is an excellent extension that protects you from cookies used by Flash applications, which often persist forever and are not clearable via normal Firefox "Private Data" clearing. Flash and all other plugins are disabled by Torbutton by default, but if you are interested in privacy, you may want this extension to allow you to inspect and automatically clear your Flash cookies for your Non-Tor usage.
- AdBlock Plus
AdBlock Plus is an excellent addon for removing annoying, privacy-invading, and malware-distributing advertisements from the web. It provides subscriptions that are continually updated to catch the latest efforts of ad networks to circumvent these filters. I recommend the EasyPrivacy+EasyList combination filter subscription in the Miscellaneous section of the subscriptions page.
- Cookie Culler
Cookie Culler is a handy extension to give quick access to the cookie manager in Firefox. It also provides the ability to protect certain cookies from deletion, but unfortunately, this behavior does not integrate well with Torbutton. Kory Kirk is working on addressing this for this Google Summer of Code project for 2009.
Request Policy is similar to NoScript in that it requires that you configure which sites are allowed to load content from other domains. It can be very difficult for novice users to configure properly, but it does provide a good deal of protection against ads, injected content, and cross-site request forgery attacks.
In addition, RSS readers such as Firefox Livemarks can perform periodic fetches. Due to Firefox Bug 436250, there is no way to disable Livemark fetches during Tor. This can be a problem if you have a lot of custom Livemark urls that can give away information about your identity.