The main page of the blog - located at blogs.amd.com - has been defaced to include the group's logo, member names and a link to its (recently opened) Twitter account.
Given that AMD uses the WordPress platform for its blog, it's very likely that the breach was the result of not keeping the software updated, allowing the attackers to exploit vulnerabilities present in some previous version.
According to TechWeek, the hackers have also got their hands on a database containing usernames, names, email addresses and encrypted passwords of AMD staff holding some 190 internal accounts, and published that information online.
The AMD blog is currently down "due to routine maintenance," says the message its front page.
Judging by the hacker group Twitter account, AMD's blog is only their second target. They have also allegedly broken into The Botting Network (a fairly popular discussion forum), defaced it and exfiltrated a file containing user usernames, emails and hashed passwords, which they promptly leaked.