Online giant Amazon, along with Wal-mart, Expedia and a whole host of other sites, have been hit by a distributed denial of service (DDoS) attack.

The DDoS attack on Neustar – which offers DNS services – affected some major hitters in the online world, with Amazon's site sluggish and even reportedly unavailable at times.

The attack started just before 5pm PST and lasted for an hour, all of the sites affected have now recovered full service.

Motivation

No motive for the attack has been uncovered, although the size of the companies involved means that this could have simply been for bragging rights.

DDoS attacks normally occur when large networks of computers – normally botnets created by hijacking PCs – are used to overtax connections.