Ubuntu Forums site was defaced by hacker with Twitter handle “Sputn1k_” Hackers have gotten every user’s local username, encrypted password, and email address from the database. Ubuntu forums.org, The popular site, has posted a message on its index page, informing its near 2 million users that it has suffered a serious security breach. Users who have used the same forum password on other sites to change it immediately. Ubuntu Forums.org and other Ubuntu/Canonical services not affected.
Source: https://thehackernews.com/2013/07/ubuntu-forums-hacked-by-Sputn1k.html