- Local Shared Object
A Local Shared Object (LSO) is a collection of cookie-like data stored as a file on a user's PC. LSOs are used by all versions of
Adobe Flash Player and Version 6 and above of Macromedia's now-obsolete Flash MX Player [cite web| url=http://www.adobe.com/products/flashplayer/articles/lso/ | title=What are local shared objects?| accessdate=2007-12-05| publisher=Adobe] .Security Issues
Flash Players use a sandbox security model. With the default settings, Adobe Flash Player does not seek the user's permission to store LSO files on the hard disk. LSO's contain cookie-like data stored by individual web sites or domains. Any kind of text data can be stored, some of which may be cause for privacy concerns.
Local Shared Objects are not temporary files. Users can opt-out of them on a per-site bases by right-clicking and selecting 'Settings', or can opt-out globally by using the Global Security Settings ( [http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager03.html#117498] ) control panel hosted by Adobe.
Privacy Concerns
As with cookies, some online advertisers use LSOs for tracking purposes. [cite web| url=http://www.informationweek.com/news/showArticle.jhtml?articleID=160901743 | title=Flash Player Worries Privacy Advocates| accessdate=2007-12-05| publisher=InformationWeek] The average internet user who may be aware of the potential privacy concerns of cookies are usually unaware of LSO's.
Unlike traditional cookies, LSO's have no expiration dates, so the information contained in those LSOs may persist indefinitely.
Additional information is available at the Electronic Privacy Information Center's [http://www.epic.org/privacy/cookies/flash.html Local Shared Objects — "Flash Cookies"] page.
Location of LSO Files
The default storage location for LSO files is operating-system dependent.
* Windows: LSO files are stored typically with a ".SOL" extension, within each user's Application Data directory, under MacromediaFlash Player#SharedObjects.
* Mac OS X: For Web sites, ~/Library/Preferences/Macromedia/Flash Player. For AIR Applications, ~/Library/Preferences/ [package name (ID) of your app] .
* GNU-Linux: ~/.macromediaFirefox Extension "Objection"
For the
Firefox Web browser , there is an extension called [http://objection.mozdev.org/ Objection] [cite web| url=http://forum.addonsmirror.net/index.php?showtopic=3133&hl=objection| title=Addons Mirror| date=2007-06-07 | accessdate=2007-12-05] [cite web| url=http://objection.mozdev.org/ | title=Objection web site| accessdate=2007-12-05] that allows the user to view and delete LSOs.Programming
The Flash Player allows Web content to read and write LSO data to the computer's local drive on a per-domain basisweb cite| url = http://download.macromedia.com/pub/flash/whitepapers/security.pdf | title = Macromedia Flash MX Security| publisher=Adobe | date=2002-03-01 | accessdate=2007-12-05] ; such data may preserve session state and record user data and behaviorcite web| url=http://www.epic.org/privacy/cookies/flash.html| title=Local Shared Objects -Flash Cookies| publisher=Electronic Privacy Information Center| date=2005-07-21| accessdate=2007-12-05 | publisher=
Electronic Privacy Information Center ] .A Flash application may store up to 100kb of data to user's hard drive (browser cookies have a limit of just 4kb). The defined storage sizes are 0kb, 10kb, 100kb, 1Mb, 10Mb, and Unlimited. If the current limit is exceeded, the user is shown a dialog requesting storage space of the next size. The user may override the amount manually by clicking the Flash application with right mouse button and selecting Settings; however, this applies only to the domain of the Flash movie. If the selected setting is smaller than the current data size, the data is deleted.
Global LSO settings may be amended by the user, by browsing Adobe's Web page that invokes Adobe's "Global Settings Manager" control panelcite web| url=http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager.html| title=Global settings manager| publisher=Adobe |accessdate=2007-12-05] [cite web| url=http://www.adobe.com/go/52697ee8| title=TechNote: How to manage and delete local shared objects?| publisher=Adobe |accessdate=2007-12-05] .
LSO Editors and Toolkits
Operating-System Support
References
External links
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