LEFTEROS / PERSONAL NOTES
Flash cookies and how to get rid of them
4 June 2010 / Lefteris Iliadis / SomniusX
Historical text from HellasProject (2009–2014). It is not current advice or a present-day service.
Imagine a cookie that:
- Stays on your computer for unlimited time
- Stores at least 100kb of data and has no size cap
- Is not detected by your browser
- Sends data about the sites you visited, without your permission
- Can revive HTTP cookies
- Even if you use more than one browser, the cookie works in all of them
And yet they exist. They are called Local Shared Objects and they are a core part of Flash. If you think private browsing will save you, you lose. Your browser does not know (and has no way to know) that you received these cookies, because Flash loads them.
Flash has no settings for the private information it stores on your machine, so what do we do? Iamasuper suggests first going to Macromedia’s site (the company that made Flash before Adobe bought it) and using the Website Storage Settings panel. You will see a small gadget written (of course) in Flash. On the rightmost tab, Delete All Sites will erase all LSOs on your computer. To stop sites putting LSOs on your machine, go to the Website Storage Settings panel, on the second tab move the slider from 100kB to zero, and untick “Allow Third Party Flash Content to store data on your computer”.
If you are on Linux and want to get rid of Flash, there is a more direct solution: type this in a console, as Sam Ruby suggests.
rm -rf ~/.macromedia/Flash_Player/#SharedObjects/*/*
chmod 0500 ~/.macromedia/Flash_Player/#SharedObjects/*
rm -rf ~/.macromedia/Flash_Player/macromedia.com/support/flashplayer/sys/*
chmod 0500 ~/.macromedia/Flash_Player/macromedia.com/support/flashplayer/sys
Firefox users can install the BetterPrivacy add-on, and Chrome users Click&Clean.
Source: ElKosmas.gr, written by Eleftherios Kosmas