ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Security
A sandbox bridge can provide this functionality. By default, content loaded externally into an AIR application at
runtime does not have access to any methods or properties in the main application. With a custom sandbox bridge
implementation, a developer can provide services to the remote content without exposing these methods or properties.
Consider the sandbox bridge as a pathway between trusted and untrusted content, providing communication between
loader and loadee content without exposing object references.
For more information on how to securely use sandbox bridges, see “Scripting between content in different domains”
on page 1075.
Protection against dynamically generating unsafe SWF content
Adobe AIR 1.0 and later
The Loader.loadBytes() method provides a way for an application to generate SWF content from a byte array.
However, injection attacks on data loaded from remote sources could do severe damage when loading content. This is
especially true when loading data into the application sandbox, where the generated SWF content can access the full
set of AIR APIs.
There are legitimate uses for using the loadBytes() method without generating executable SWF code. You can use
the loadBytes() method to generate an image data to control the timing of image display, for example. There are also
legitimate uses that do rely on executing code, such as dynamic creation of SWF content for audio playback. In AIR,
by default the loadBytes() method does not let you load SWF content; it only allows you to load image content. In
AIR, the loaderContext property of the loadBytes() method has an allowLoadBytesCodeExecution property,
which you can set to true to explicitly allow the application to use loadBytes() to load executable SWF content. The
following code shows how to use this feature:
var loader:Loader = new Loader();
var loaderContext:LoaderContext = new LoaderContext();
loaderContext.allowLoadBytesCodeExecution = true;
loader.loadBytes(bytes, loaderContext);
If you call loadBytes() to load SWF content and the allowLoadBytesCodeExecution property of the
LoaderContext object is set to false (the default), the Loader object throws a SecurityError exception.
Note: In a future release of Adobe AIR, this API may change. When that occurs, you may need to recompile content that
uses the allowLoadBytesCodeExecution property of the LoaderContext class.
Best security practices for developers
Adobe AIR 1.0 and later
Although AIR applications are built using web technologies, it is important for developers to note that they are not
working within the browser security sandbox. This means that it is possible to build AIR applications that can do harm
to the local system, either intentionally or unintentionally. AIR attempts to minimize this risk, but there are still ways
where vulnerabilities can be introduced. This topic covers important potential insecurities.
Last updated 6/6/2012
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