Hashemian Blog: Adobe Flash Cookies, Local Storage

Adobe Flash Cookies, Local Storage

Call me paranoid, but I always like to be clear on what a site is doing on my computer while I have it up on my browser. I don't think I'm that paranoid (okay, maybe a little,) but I think users are entitled to know if a site is storing and reading data to and from their computers. That's an exact description of what browser cookies are used for, but tonight I learned about a new kind of cookie I had been abashedly unaware of.

I for one, don't appreciate being followed around while I surf the Net, so I delight in cleaning or modifying my cookies often and throwing off the trackers. But tonight I was stumped by an often visited music site that remembered me steadfastly, even when I deleted my cookies and visited the sites on different browsers.

What was going on here? Was the site using my IP address to identify me? I doubted it. IP address tracking is so inexact these days that it's generally only used for geo-location, and even that yields questionable results. After some persistent searching, I finally found the elusive answer, and it was a Flash cookie.

I had never known that Flash player could store data on users' computers, so I delved a bit deeper. I found out that they are similar to, but work completely independently from browser cookies. On my Windows XP machine, Flash cookies (known as local storage in Macromedia's jargon) are stored under the "\Documents and Settings\[account]\Application Data\Macromedia\Flash Player\#SharedObjects\" folder. By default each site is allowed to store and access up to 100KB in the cookies and users are oblivious to this activity the whole time.

Way to go Adobe. I don't remember every seeing anything about these cookies when I was installing the Flash player. No doubt it was buried in some privacy legalese. The good news is that once discovered, these cookies can be deleted using Adobe's Website, or by just simply zapping them in the folder mentioned above. Adobe's site also allows users to disable Flash cookies altogether. The caveat is that just like browser cookies, many sites rely on these cookies and probably will not function correctly without them. For me, the happy medium was to configure Flash to alert me every time a site wants to store a Flash cookie on my PC. You can do the same by going to Global Storage Settings panel on Adobe's Flash site and alter your settings to match the figure below.

Maybe you can't stop sites from storing and retrieving data from your computer, but at least you know who's tracking you using this type of cookie.

flash cookies,flash local storage,adobe,macromedia,flash,cookies,browser cookies,browsers,flash player
Labels: browsers, web
<Adobe Flash Cookies, Local Storage>

// posted by rh

2 comments

2 Comments:

By Anonymous, at 17/11/07 9:15 PM

good info. thanks

By Kevin, at 9/1/09 12:36 AM

Thanks my Friend.... This one stumped me for the past 2 WEEKS! Each time I went to "that site," I was amazed as to how it "knew" me. I even tried accessing it through proxies, etc, no affect. Long story short, you nailed it on the head.

Kevin