A Turkish hacker group diverted traffic to a number of high-profile websites including the Telegraph, UPS, Betfair, Vodafone, National Geographic, computer-maker Acer and technology news site the Register on Sunday night, putting unwary users at risk of having passwords, emails and other details stolen.
Industry experts warned people not to log into sites such as Betfair because their details could be stolen.
Some people viewing the sites thought that they had been hacked directly, with the sites appearing to show a message in Turkish by a group called Turkguvenligi, who last month carried out a similar attack on a Korean company.
But in fact the sites themselves remained unaffected. The group had instead attacked the domain name system (DNS), which is used to route users to websites. A list of sites affected by the hack, including Microsoft in Brazil and Dell in South Korea, was posted on the zone-h website, used by hackers to list their successes — via redwolf.newsvine.com