The hacker group Anonymous claimed on Tuesday to have taken out 5,500 Twitter accounts linked to the Islamic State group, which claimed responsibility for the Paris attacks.
The loosely organised hacking collective made the claim in a tweet one day afterlaunching #OpParis campaign , which stepped up an earlier effort to shut down social media accounts of the organization.
“We report that more than 5500 Twitter account of #ISIS are now #down! #OpParis #Anonymous #ExpectUs,” said a tweet posted on Tuesday which followed a video message posted Monday.
It was not immediately clear how the accounts would have been disabled. But the hacker group said it posted the accounts to an online forum labeling them as #daeshbags, a reference to Daesh, an Arabic acronym for the Islamic State group.
In an apparent riposte, a message posted via the messaging service Telegram calls on Islamic State affiliates to secure their Internet communications.
“The #Anonymous hackers threatened… that they will carry out a major hack operation on the Islamic state (idiots),” the message said.
Anonymous has waged a long-running campaign against the Islamic State group but stepped up the effort following the attacks last Friday in the French capital.
In a video posted online on Monday, a man wearing a Guy Fawkes mask said the Islamic State militants who claimed responsibility for the Paris attacks were “vermin” and Anonymous would hunt them down.
“These attacks cannot remain unpunished,” the man said in the video, speaking in French.
“We are going to launch the biggest operation ever against you. Expect many cyberattacks. War has been declared. Get ready,” the man said, without giving details of what the attacks would involve. “We don’t forgive and we don’t forget.”
Anonymous is an international network of activist computer hackers which has claimed responsibility for many cyberattacks.
Other hackers groups fighting the IS
The Paris attacks have brought an increase in online activity against the jihadists. Even as Anonymous draws much attention for its campaign against Islamic State, other groups claim to have been doing more for longer.
One group that feeds information to the US government says it has suppressed tens of thousands of Twitter accounts since January, and its members have posed as would-be recruits to gain information on so-called Dark Web operations supporting the Islamic State.
“We’re playing more of an intelligence role,” said the executive director of Ghost Security Group, who declined to be named, citing security concerns.
The group is a volunteer organisation that has been sending data to the FBI and other agencies via a Congressional terrorism adviser, Michael S Smith II.
Smith said the group’s infiltration efforts had given some actionable information to the government, and that coordinated complaints to Twitter had helped push Islamic State supporters elsewhere.
US agencies “appreciate the outside support. I have constant feedback to that,” Smith said.
The FBI declined to comment.
Smith, chief operating officer of defence contractor Kronos Advisory, said Ghost Security Group contacted him in June and provided screenshots of internal communications about an impending attack in Tunisia, which he said he passed along and which helped break up a militant cell in time.
Facebook this year banned any praise of “terrorist” groups on its site. YouTube now acts to take down violent videos within hours, Ghost Security Group said.
At Twitter, Ghost Security Group and an affiliate now circulate lists of problem accounts. Ordinary users who see those lists can then complain about those accounts, getting them suspended more quickly than if the groups were acting alone.
The pressure on Twitter is one reason that Islamic State has moved a lot of its broadcast communication to Telegram, which opened a “channels” service that lets a participant reach thousands of viewers, Berger and other security experts said.