The Anonymous group said their Twitter accounts have been hacked by another rival group known as Rustle League, which also took over other accounts from Burger King, Jeep and BBC Top Gear.
There is major concern going on at Twitter of other possible breached accounts that haven’t been made public yet. It’s not clear on how many accounts have been breached by the hackers.
The Anonymous group had over 160,000 followers prior to its security breach.
Experts warn that users need to strengthen their passwords.
“The reason Anonymous fell victim is probably human weakness,” said Graham Cluley, senior consultant at security firm Sophos. “Chances are that they followed poor password practices, like using the same password in multiple places or choosing a password that was easy to crack.”
Cluley explained that everyone should learn better password security techniques, such as using at least one number in their passwords.
“if it can happen to an account run by Anonymous supporters, it could happen to you,” he said.
On Monday, the account for Burger King was breached and on Tuesday that of Chrysler-owned Jeep was broken into.
One message on the Burger King account claimed that the company had been sold to McDonalds while the Jeep account tweeted about rival cars.
Meanwhile, BBC presenter Jeremy Clarkson’s account was hacked by spammers advertising weight-loss tablets.
Twitter has told its account holders that they need to be smarter with their passwords.
In a blog post published on Tuesday, Bob Lord, director of Information Security, said: “Over the past couple of days, there’s been a fair amount of conversation about account security on Twitter,”
He urged users to have strong passwords. “Your password should be at least 10 characters that include upper and lower case characters, numbers and symbols,” he said.
The Anonymous hack on Thursday morning was short-lived. Three hours later, those running the feed tweeted that they had gained back control of their account.
As well as raising issues about password security on Twitter, the incident also raises questions about the status of Anonymous.
But in a recent report, security firm McAfee suggested that Anonymous could fall into decline this year.
“Many are starting to prefer making a profit over a political point, not only through carrying out actions themselves but also offering a hacking-as-a-service to those less technically able.”,” said Raj Samani, McAfee’s chief technical officer for Europe, Middle East and Africa.
“The authorities have launched a crackdown on Anonymous and quite a number of its key members have been arrested,” he added.
Much of the focus on cyber crime has shifted this week to the extent and scale of Chinese hacking.