Islamic State forced to issue anti-hack guidelines after threat by Anonymous

The cyber branch of the so-called Islamic State has issued a set of basic guidelines to help protect followers from being targeted by hacking group Anonymous.

In the wake of the terror attacks in Paris, the global hacking collective "declared war" on the extremist militant group, warning of their "biggest operation ever".

In response, Islamic State sent out a message via secret messaging app Telegram, labelling Anonymous "idiots" but urging their "brothers" to take precautions.

Read: Anonymous 'declares war' on Islamic State militants

The message, sent from the Khilafah News channel under the header #Warning, read: "The #Anonymous hackers threatened in new video release that they will carry out a major hack operation on the Islamic state (idiots)."

The note, picked up by the International Centre for the Study of Radicalisation in London, included tips such as using VPN to regularly change IP address, not talking to people they do not know via Telegram or Twitter, and not using the same Twitter username as e-mail handle.

Nick Kaderbhai, a research fellow from the think tank told the Huffington Post UK that anyone could technically subscribe to the channel, but added: "The more IS channels you subscribe to the more open you are to investigation."

Anonymous first declared its intention to target the online accounts of Islamic State militants in January, after three days of terror which began with the killing of staff at French satirical magazine Charlie Hebdo.

Read: Anonymous hackers warn terrorists: We are coming for you

Since then, according to an investigation by Foreign Policy, hackers have taken down 149 websites promoting Islamic State propaganda and exposed or suspended 101,000 Twitter accounts and 5,900 propaganda videos.