This is not a traditional virus, but a script problem affecting
only users of WebTV appliances.
This program works by injecting a script to signatures of people
when they post messages to public newsgroups. When other WebTV
users read such a message, they will automatically post messages
to same newsgroups with the same infectious signature. Eventually
this will overload these newsgroups with phony messages.
The WTV/Flood script does not need any local user storage to
operate. WebTV has extended HTML with tags of its own - tags
that instruct WebTV server to, for example, post a message.
That's exactly how WTV/Flood replicates; it uses these WebTV
F-Secure Anti-Virus does not work under WebTV.
[Mikko Hypponen, F-Secure]