We regularly block undesirable file types etc through BM's proxy by file extension, but we've noticed a new (for us) way that users are getting files in. They install a browser add-in of some kind and download using the proxy but without file extensions.

See http://downloads-zdnet.com.com/WAV-t...ml?tag=lst-0-6 and click on "Secure Download" for an example.

Does anyone know a good way of blocking these browser add-ins? I've tried unchecking the "Enable install on demand" and "Enable third-party extension" checkboxes in IE6 but they don't seem to stop them.

Any assistance appreciated.