In Flash Player's security model, Flash applications and SWF files on a local computer are not allowed to communicate with both the Internet and the local file system by default. A local SWF file is a SWF file that is locally installed on a user's computer, not served from a website, and does not include projector (EXE) files.
The restrictions that are discussed in this section do not affect SWF files that are on the Internet.
When you create a FLA file, you can indicate whether a SWF file is allowed to communicate with a network or with a local file system. In previous versions of Flash Player (7 and earlier), local SWF files could interact with other SWF files and load data from any remote or local location. In Flash Player 8 and later, a SWF file cannot make connections to the local file system and the Internet. This is a safety change, so a SWF file cannot read files on your hard disk and then send the contents of those files across the Internet.
This security restriction affects all locally deployed content, whether it is legacy content (a FLA file created in an earlier version of Flash) or created in Flash 8 and later. Suppose you deploy a Flash application, using Flash MX 2004 or earlier, that runs locally and also accesses the Internet. In Flash Player 8 and later, this application now prompts the user for permission to communicate with the Internet.
When you test a file on your hard disk, there are a series of steps to determine whether the file is a local trusted document or a potentially untrusted document. If you create the file in the Flash authoring environment (for example, when you select Control > Test Movie), your file is trusted because it is in a test environment.
In Flash Player 7 and earlier, local SWF files had permissions to read from both a local file system and the network (such as the Internet). In Flash Player 8 and later, local SWF files can have the following levels of permission:
Access the local file system only (default) A local SWF file can read from the local file system and universal naming convention (UNC) network paths but cannot communicate with the Internet. For more information on local file access SWF files, see Access local files only (default).
Access the network only A local SWF file can access the network (such as the Internet) but not the local file system where it is installed. For more information on network-only SWF files, see Access network only.
Access to the local file system and the network A local SWF file can read from the local file system where it is installed, read and write to and from servers, and can cross-script other SWF files on either the network or the local file system. These files are trusted, and behave like they did in Flash Player 7. For more information on local and network access SWF files, see Access file system and network.
For more information on local file security in Flash 8 and later as it pertains to the authoring tool, see the following sections:
- Understanding local security sandboxes
- About Flash Player security settings
- About local file security and projector files
- About troubleshooting legacy SWF files
- Fixing legacy content deployed on local computers
- Publishing files for local deployment
For information about local file security for users, see About Flash Player security settings. For more information on security, see www.adobe.com/devnet/security/ and www.adobe.com/software/flashplayer/security/.