Local Shared Objects: the cookies you never knew that existed

Many users, specially those who are worried about privacy, already know cookies: how they work, where are they saved and, most imprtantly, how to delete them. Most browsers include an utility to manage them, blocking or deleting the ones we don’t want.

But even if you are actively deleting cookies, you might still be leaving something behind. Local Shared Objects are the implementation of cookies done by Adobe Flash. So, if you have this software installed (and most people do) these Flash cookies are resting on your hard disk, maybe forever.

Each site using Flash can store, by default, up to 100 KB of data in your computer, even without you knowing it. No permission is asked unless the application tries to store more data than permitted.

This data is save in the following lcoations:

• In Windows: C:\Documents and Settings\[user]\Application Data\Macromedia\Flash Player
• In Mac OS X: /Users/[user]/Library/Preferences/Macromedia/Flash Player
• In Linux: ~/.macromedia

So, how can we manage these Flash cookies? The Adobe Flash Player Settings Manager is a small Flash program by Adobe which will allow to view the stored Local Shared Objects, delete them and limit the quantity of data each site is allowed to save.

We can even block the Flash cookies completely from the Global Storage Settings Panel, unchecking the Allow third-party…

There are also some applications that allow manipulation of the Local Shared Objects, like SolVE, which works in Windows and Mac:

or Sol Editor, only for Windows.

So, are you going to protect your privacy or you don’t mind any marketer being able to spy on you? Yes, this is technically feasible and has already been done. Adbrite and Google ad manager are already storing data on your Flash cookies, who knows how many more will do it?