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File Quarantine

Starting in Mac OS X v10.5, applications that download files from the Internet or receive files from external sources (such as email attachments) can assign quarantine attributes to the file using a function in Launch Services. The attributes associate basic information with the file, such as its type, when it was received, and the URL from which it came. When the Finder or any other program uses Launch Services to open a quarantined file, Launch Services inspects the file to see if it appears to be an application, script, or other executable file type. If so, the system displays an alert informing the user that the file is an application and asking for confirmation that it should be executed. The alert lets the user open the URL from which the file was downloaded, launch the program, or cancel. If the user proceeds to open the file, Launch Services removes the quarantine attributes from that file.

If you are developing a web browser or email program, or if your software somehow deals with files from unknown sources, you should use the Quarantine feature as part of your program’s basic security procedures. Quarantine is part of the Launch Services API, which is itself part of the Core Services framework. For more information about the Quarantine feature, see Launch Services Release Notes.

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