678 Understanding Security
In Flash Player 7 and later, if a version 6 (or earlier) SWF file attempts to load data from a
server that resides in another domain, and that server doesn’t provide a policy file that allows
reading from that SWF file’s domain, the Macromedia Flash Player Settings dialog box
appears. The dialog box asks the user to allow or deny the cross-domain data access.
If the user clicks Allow, the SWF file can access the requested data; if the user clicks Deny, the
SWF file cannot access the requested data.
To prevent this dialog box from appearing, you should create a security policy file on the
server providing the data. For more information, see “Allowing cross-domain data loading”
on page 702.
Flash Player 7 and later do not allow cross-domain access without a security policy file.
Flash Player 8 changed the way it handles
System.security.allowDomain. A Flash 8 SWF
file that calls
System.security.allowDomain with any argument, or any other SWF file that
uses the wildcard (
*) value, permits access only to itself. There is now support for a wildcard
(
*) value, for example: System.security.allowDomain("*") and
System.security.allowInsecureDomain("*"). If a SWF file of version 7 or earlier calls
System.security.allowDomain or System.security.allowInsecureDomain with an
argument other than wildcard (*), this will affect all SWF files of version 7 or lower in the
calling SWF file’s domain, as it did in Flash Player 7. However, this kind of call does not
affect any Flash Player 8 (or later) SWF files in the calling SWF file’s domain. This helps
minimize legacy content breaking in Flash Player.
For more information, see “About domains, cross-domain security, and SWF files”
on page 694, allowDomain (security.allowDomain method), and
allowInsecureDomain (security.allowInsecureDomain method).
Flash Player 8 does not allow local SWF files to communicate with the Internet without a
specific configuration on your computer. Suppose you have legacy content that was published
before these restrictions were in effect. If that content tries to communicate with the network
or local file system, or both, Flash Player 8 stops the operation, and you must explicitly
provide permission for the application to work properly. For more information, see “About
local file security and Flash Player” on page 679
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