Busy.. Ready… What?

This work is licensed by Randall Munroe/XKCD under a Creative Commons Attribution-NonCommercial 2.5 License.
This means you’re free to copy and share these comics (but not to sell them). More details.

Using Firefox we may adjust some settings in order to safer surf the web:

• edit privacy preferences: do not remember visited pages (or not too long),
• edit privacy preferences: do not remember downloads,
• edit privacy preferences: do not remember what you enter in forms and the search bar,
• edit security preferences: do not remember passwords for site or at least use a master password,
• edit security preferences: accept cookies only until you close Firefox,
• edit security preferences: always clear private data when you close Firefox (history, form information, cache, cookies, passwords, sessions)
• edit content preferences: disable Java,
• edit advanced preferences: set cache size to < 10 MB,
• install Scroogle (SSL) and/or Ixquick SSL search engine add-on in your preferred language,
• install Better Privacy add-on to automatically empty Flash cookies,
• install Vidalia Bundle add-on which contains Tor, Privoxy and the Torbutton to surfer anonymously whenever you want to,
• install AdBlockPlus to avoid intrusive ads,
• install Flashblock add-on to decide whether you want to see a Flash animation or not anytime.

Firefox users may since a long time automatically delete website cookies or even disable them. But did you know there is another way to track website visitors? The so-called “Flash cookie” or Local Shared Object is a Flash feature that allows Flash developers to store a cookie directly via Flash to a user’s computer. But there is no mechanism to set an expiry date on these cookies, so they will stay close to forever on your computer.

The LSO may be accessed only by the domain which created it. Flash player’s default setting allows each domain to store 100kB of information on a user’s computer. Right-clicking on a Flash video whatsoever allows to readjust this amount to 0 and to specify if you are willing to accept even 3rd party LSOs.

Flash cookies are stored in a special directory depending on the operating system on the client machine. They are arranged in directories according to the site that placed them on the computer (look for a file with a .SOL extension):

• Windows: C:\Documents and Settings\[username]\Application Data\Macromedia\Flash Player
• Macintosh OSX: /Users/[username]/Library/Preferences/Macromedia/Flash Player
• GNU/Linux: ~/.macromedia

My #SharedObjects directory is full of cookie information :

To visualize the contents of these cookies and to delete them, Firefox users are encouraged to install the extensions Objection (allows to read the contents of LSOs and to delete them) or BetterPrivacy (this one allows automatic deletion of LSOs).

Power users may write a cronjob that empties the .macromedia folder regularly:

user@machine:~$ crontab -e
# m h dom mon dow command
0 1 * * * rm -rf ~/.macromedia/Flash_Player/#SharedObjects/

will empty the folder every hour.

Read more:

• http://en.wikipedia.org/wiki/Local_Shared_Object
• http://epic.org/privacy/cookies/flash.html
• http://www.adobe.com/products/flashplayer/articles/lso/

A very complete guide for those who need to publish information circumventing oppressive state policies that do not respect freedom of speech : http://advocacy.globalvoicesonline.org/projects/guide/

The guide also exists in chinese.

Our favourite austrian singing philosphers from monochrom live at the 23C3 in Berlin.