High-profile users of microblogging site Twitter have had their accounts compromised by a hacker, who made fake posts to their accounts.
Twitter on Monday said the hacker had broken into 33 accounts by gaining access to tools used by its support team.
"These accounts were compromised by an individual who hacked into some of the tools our support team uses to help people do things like edit the email address associated with their Twitter account when they can't remember or get stuck," wrote Twitter co-founder Biz Stone in a blog post. "We considered this a very serious breach of security and immediately took the support tools offline. We'll put them back only when they're safe and secure."
Celebrities including Barack Obama, Britney Spears and US newscaster Rick Sanchez had their Twitter accounts hacked and fake messages posted, according to security blogger Graham Cluley. For example, the hacker, purporting to be Sanchez, wrote: "I am high on crack right now might not be coming into work today."
The compromised accounts came after what Stone described as a "wacky weekend" where "lots of folks were tricked into participating in a Phishing scam" aimed at Twitter users.
In the phishing attempt, scammers sent out email notifications purporting to be from Twitter that contained a link to a site "masquerading as the Twitter front page", wrote Stone in a blog post on Saturday. The object of the scam was to collect people's Twitter sign-in details, which would allow the phisher to send messages in the guise of the compromised user. In the event of a compromise, Stone said user passwords would automatically be reset and notification emails sent out.