A flaw in Microsoft's WebTV units might allow malicious hackers to force the unit's modem into dialling the emergency services, at least according to US reports.

An ABC news report suggests an email virus is spreading which can shut a WebTV (or in its rebranded form, MSNTV) unit down, reboot it and call 911. Several people have had police turn up at their door after clicking on an infected attachment, it reports.

The virus theory, although apparently endorsed by Microsoft itself, has been treated with scepticism by techies who point out the behaviour carries all the hallmarks of that well known, ageing modem exploit, +++ATH0.

Modems commonly use the Hayes Command Set but many mishandle certain command strings such as +++ATH0, which can be used to shut down modems and force them to enter command mode. This, it's suggested, is a far more likely explanation of the odd behaviour of WebTV units. ®