Comments on: Firefox’s Super Cookies

By: Pascal Meunier

Pascal Meunier — Thu, 28 Feb 2008 19:31:31 +0000

I note that IE’s userData contents is stored within index.dat files, and that there is no mechanism for auditing userData contents within IE. They are binary files. UserData storage can only be enabled or disabled in each security zone.

By: Pascal Meunier

Pascal Meunier — Wed, 27 Feb 2008 17:35:43 +0000

It’s a standard proposed by the “Web Hypertext Application Technology Working Group” (WHATWG) but apparently Microsoft isn’t part of it, if one is to believe the relevant Wikipedia article. I haven’t looked at the equivalent IE feature, thanks for mentioning it.

There are applications using Flash storage, so this is currently just a way of doing the same thing independently of Flash. I believe that in the future someone will think of a use for all that storage.

By: Stephan

Stephan — Wed, 27 Feb 2008 15:44:10 +0000

“I wonder why DOM storage isn’t used much after being available for a whole year;”

Isn’t this only available in FF? I believe IE uses “userData” (1MB storage) for local storage. Not sure about other browsers, but it seems like they have their own schemes for doing local storage, all of which are disparate.

Other than perhaps for “intranet-based” applications, utilizing local storage does not sound too efficient or reliable to me. Does anyone really need to store 1MB or even up to 5MB of persistent data client side for any useful purpose? I’ve read a lot of AJAX sites touting the usefulness, but I just do not buy their arguments…which usually amount to “pass everything off to the client and let JS handle it.” Rubbish.

By: Viewing Firefox’s Super Cookies « the back room tech

Viewing Firefox’s Super Cookies « the back room tech — Tue, 12 Feb 2008 15:01:00 +0000

[...] Super Cookies February 12, 2008 — Julie Pascal has a nice short post on Firefox’s “super cookies” and the information contained inside the browser’s DOM storage. He does a nice job [...]

By: Pascal Meunier

Pascal Meunier — Fri, 25 Jan 2008 14:12:59 +0000

Thanks RK and Julie. The limit in Firefox seems to be 5 MB (http://kb.mozillazine.org/Dom.storage.default_quota)

By: Julie Smith

Julie Smith — Thu, 24 Jan 2008 19:56:06 +0000

You can try SQLite Database Browser instead of installing sqlite3 to view the webappsstore.sqlite file. It allows you to browse the database as well as query it.

Unfortunately, I didn’t find any juicy data in my file. Like RK, I have only one entry from cnn.com. I deleted that record, then revisited cnn.com, and saw I had a new record created by the site.

Is there some type of limit or restriction on writing to DOM storage?

- Julie

By: Pascal Meunier

Pascal Meunier — Thu, 17 Jan 2008 17:59:25 +0000

Thanks Adam. Storage is organized differently in Ubuntu; the “support/flashplayer/sys” directory seems to have only access control settings, probably from the Flash management widget, and not the data. The Ubuntu version of your script is:
#!/bin/tcsh
foreach d ( ~/.macromedia/Flash_Player/\#SharedObjects/*/* )
rm -rf “$d” && touch “$d” && chmod 400 “$d”
end

and it does indeed seem to “neuter” the Flash local storage without preventing Flash applications from playing. Thanks for the tip.

By: Adam

Adam — Thu, 17 Jan 2008 16:06:41 +0000

There’s two directories, not one. This works on a Mac. YMMV.

#!/bin/tcsh

cd “${HOME}/Library/Preferences/Macromedia/Flash Player/”

foreach d ( macromedia.com/support/flashplayer/sys/* \#SharedObjects/*/* )
rm -rf “$d” && touch “$d” && chmod 400 “$d”
end

By: RK

RK — Thu, 17 Jan 2008 14:25:37 +0000

I’ve got one from CNN.com recording some “user_topics” in an array. I went back to CNN.com today and prodded some things, but received nothing new in the webappsstore.