Microsoft gives spammers an image crisis

Microsoft is to unveil new anti-spam tools for its MSN and Hotmail services, as the war on unsolicited email heats up.

Microsoft already claims to block 2.4 billion email messages targeting subscriber inboxes every day. Now the software giant intends to increase its anti-spam arsenal with a feature in MSN 8 and Hotmail which will enable subscribers to turn off images within emails, a feature that the company said would help cut down on spam.

Images may conceal so-called 'web beacons' that confirm a particular email address is in use. That's important to spammers, who frequently use dictionary attacks that blanket domains with thousands of random variations in the hope of hitting a handful of targets. Beacons can be triggered when images appear in a preview window, meaning recipients do not need to open the file to be painted as a target.

The announcement comes as online services are increasingly touting anti-spam features to differentiate their products from rivals amid fierce competition for subscribers.