Archive for May, 2010

On his blog, Wladimir Palant complains about Google providing browser users with a not effective enough way to opt-out from Google Analytics.

Specifically, he doesn't like how the Google Analytics Opt-out Browser Add-on actually allows Google Analytics scripts to load and run, just setting a global variable (

_gaUserPrefs

) in the hosting page which tells the code not to send back data.

This approach is inherently flawed, because the hosting page can easily force Google Analytics to run by simply overwriting the aforementioned

_gaUserPrefs

variable.

Worse, the

_gaUserPrefs

variable is automatically added to every single page you load. Hence, the fact itself you're using this "opt-out" add-on can be easily detected if you keep JavaScript enabled, adding some extra points to your unanonymity score. Something like

if (!!_gaUserPrefs) alert("You hate Google Analytics, don't you?")

can make a nice test to update the Panopticlick suite with, singling out privacy concerned persons.

However, the original sin is that the Google Analytics' script still being downloaded and executed, and if you find this questionable from a security/privacy perspective, then the Google's Analytics Opt-Out Browser Add-on serves no purpose.

Wladimir's post initially advertised his own extension as a better solution, but later he had to retract:

Still, until Google can come up with something better I recommend people to use Adblock Plus with EasyPrivacy filter subscription, that’s the easy and reliable solution (check the update below).

Update: Sorry, that last part wasn’t entirely correct — EasyPrivacy doesn’t block Google Analytics script either, due to many websites being broken without it as mentioned above.

True, if you block Google Analytics' script by using a proxy, a firewall, a host file or Adblock Plus with an ad-hoc filter, many sites are going to break because they depend on JavaScript objects provided by Google Analytics. They integrate GA calls within essential functionality, such as link and button event handlers or even initialization routines, and they fail more or less dramatically when the script is missing. Sad, silly but true.

This is no news (and no problem) at all for NoScript users, though: in fact, almost one year and half ago, this very issue prompted the development of NoScript's Script Surrogates feature, which prevents the breakage by "emulating" the blocked script with dummy replacements. This means that NoScript users have Google Analytics blocked by default, with no site-breaking side effects.

So, until Google can come up with something better I recommend people to use the reliable and easy solution ;)

I'm receiving several reports by Ubuntu and Debian users having their desktops crashed as soon as they click the NoScript icon. Yes, your whole session gone, back to your logon page in one move!

Actually this may be triggered by different actions, not necessarily with NoScript installed, or reportedly just by having a long/complex enough interaction with Firefox.

It turns out to be a bug in the xorg-server package, which Ubuntu's maintainers deemed not worth to get fixed before releasing Lucid Lynx.

My understanding is that a fix will be included in next automatic update, but in the meanwhile you can apply the available patch from Bryce Harrington's PPA by issuing the following commands in a terminal:

sudo add-apt-repository ppa:bryceharrington/purple && sudo apt-get update && sudo apt-get upgrade

Update

I was sure I had this crash reported by Debian users as well, but when some of them commented here that they couldn't reproduce it, I double checked and could find Lucid Lynx reporters only. Better so.

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