The FileAttributes tag is new to version 8. It must be present in all movies version 8 and over. It must be the very first tag in the SWF movie. It should be unique (other instances will be ignored.)
The f_has_metadata flag shall be set to 1 whenever the movie includes a Metadata tag.
The f_allow_abc flag shall be set to 1 to give the player the right to execute DoABC scripts (this is a version 9 flag, in version 8, keep it set to 0.)
The f_suppress_cross_domain_caching must have some effect over the caching of some things... (version 9+)
The f_swf_relative_urls means that URLs specified in the movie are relative to the URL where the movie was loaded from. (version 9+)
The f_use_network flag needs to be set to 1 in order for the movie to be given the right to access the network. By default, a local movie will be allowed to load other local movies but nothing from the network.
I'm not registered as a security expert. However, this tag does not solve any security issues. It is a mimic just like the Protect, ProtectDebug and ProtectDebug2 tags. If you are playing a flash animation from a hacker, the fact is that it can include anything it wants and hack your system if the player has a flaw. Only a player without any flaws will be safe.