A group of Turkish hackers have claimed defacements on a host of tech-related websites, including the Register news website, Acer and Vodafone.
Yesterday evening UK time, the Daily Telegraph was also defaced, along with National Geographic and UPS websites, according to the hackers.
The claims appeared on the Zone-H.org the hack ranking website which IT Pro explored last year in a report on web graffit.
Currently, the Register website is still down, whilst the others appear to be up and running.
An update from the Register has been sent out, however. It claimed its service provider had not been in touch. Later it tweeted its DNS records had been "restored to normality."
"It's been a frustrating few hours. But we can tell you the Register's website was not breached," the publication said.
"And as far as we can tell there was no attempt to penetrate our systems. But we shut down access/services in other words, anything that requires a password as a precaution."
Vodafone said it was looking into the situation as well.
"We're aware that DNS entries were altered for a large number of major corporate and media organisation websites - including vodafone.com - causing some web users to be redirected," a spokesperson said.
"We're investigating the matter. vodafone.com - does not contain any customer information and its content is not affected."
The hackers, known as Turkguvenligi, said they managed to change the DNS records for those sites by compromising Netnames.co.uk and Ascio. At the time of publication, neither Netnames.co.uk nor Ascio had replied for a request for comment.
"First we target site itself. if we can't find a vuln [vulnerability]. on the script of site we try accessing server or vps [virtual private server]. If none of them works we try domain company," the hackers told the Guardian.
"The hardest one is reaching the domain company but if you can succeed there will be a treasure for you."
Graham Cluley, senior technologist at Sophos, said problems for those affected by the hack could last for a significant period of time.
"Because of the way that DNS works, it may take some time for corrected DNS entries for the affected websites to propagate worldwide - meaning there could be problems for some hours ahead," Cluley said in a blog post.
"In many ways we have to be grateful that the message displayed appears to be graffiti, rather than an attempt to phish information from users or install malware."
