A number of high-profile websites were hacked on Sunday by a Turkish hacking group TurkGuvenligi, who have described the 4th of September as ‘World Hackers Day’.

Websites including Vodafone,  UPS, The Daily Telegraph, The Register, BetFair and Acer were among those targeted, as the attackers redirected users to their own home page.

Zone-H – a global security intelligence website reported that 186 websites were targeted in the attack, and domain names management provider NetNames, confirmed that some of its customer domains were affected.

“At approximately 2100BST on Sunday 4 September 2011 a very small number of customer domains were redirected to an unauthorised domain name server (DNS server). This was done by placing unauthorised re-delegation orders through to the registries via our provisioning system,” the firm explained in a statement.

“These orders updated the address of the master DNS servers responsible for serving data for these domains. The rogue name server then served incorrect DNS data to redirect legitimate web traffic intended for customer web sites through to a hacker holding page branded TurkGuvenligi. The unauthorised orders were added by using a SQL injection attack to gain access to a number of our customer accounts. The illegal changes were reversed quickly to bring service back to the customers impacted and the accounts concerned have been disabled to block any further access to the systems.”

The attacks came just days after Dutch security certificate authority DigiNotar confirmed it was hacked and fake SSL certificates were issued. A list published by the Dutch Government has now provided insight into the scale of the attacks, revealing that 531 rogue certificates were issued, including the MI6 website, the CIA, Facebook, Google, Skype, Twitter and WordPress.

The Dutch Government confirmed it is looking into reports that Iran was responsible for the hacks.