Adobe developed a rich Javascript-like language called ActionScript to provide scripting capabilities to Flash. One of the interesting features of ActionScript is its ability to send HTTP requests to 3rd party sites through the browser which invoked it. This is where Flash becomes interesting security-wise. With Flash it is possible to shape an outgoing request to a 3rd party site in ways not available from within "standard" Javascript. Specifically of interest is Flashs ability to send arbitrary HTTP request headers with outgoing HTTP requests.
