Sophos Antivirus discovered a proof-of-concept virus that infects Macromedia Flash files. Flash files offer speedy graphic animation rendition on multimedia Web sites. The virus, called SMF/LMF-926, is the first of its kind to infect Flash files. Simply visiting a Flash-enabled site won't infect a user's machine because the virus only affects Flash files run on a standalone Flash player and not the Web browser plug-in version. A user must download or receive a Flash file through email and open the file before the virus becomes active. Even then, the virus is relatively harmless--it infects only other Flash files and doesn't damage a user's system. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />When a user activates the virus, the virus displays a message on the user's screen that reads "Loading Flash Movie" while showing a numeric puzzle on the screen for users to try to solve as the virus creates a program that infects other Flash files on the user's system. The virus does not affect Macromedia Shockwave files. Macromedia is aware of the problem and said it will issue a patch for the product next week. In the meantime, Macromedia released a program that users can download to clean the virus from their systems. The program removes file-type associations for .swf files, which are related to Flash movie files so that when a user downloads an .swf file, Windows prompts the user to choose an application to open the file, at which point the user should not open the file at all. Macromedia said that reinstalling the soon-to-be available patched version of the standalone Flash player will remap the .swf file-type association so users can open and view Flash animation files.