Jihadis have hacked tens of thousands of Twitter accounts in retaliation for the drone attack that killed a British Islamic State [Daesh] extremist.
A group called Cyber Caliphate, set up by Junaid Hussain from Birmingham, urged its followers to take control of the accounts to spread IS propaganda. Most of the victims appear to be based in Saudi Arabia, though some are feared to be British.
In what experts described as a worrying escalation of the global cyber war, details of more than 54,000 Twitter accounts, including passwords, were posted online last Sunday.
It raised the prospect of genuine account holders watching helplessly as IS rhetoric appears under their names.
One victim, a half-British engineer based in Saudi, said: 'I am horrified at how they got hold of my details.'
The extremists also posted hacked personal details, including mobile phone numbers, of the heads of the CIA, the FBI and America's National Security Agency.
Hussain led IS's computer hacking division before he was killed by a US drone in a joint operation with the UK in August. His widow, mother-of-two Sally Jones from Kent – known as 'Mrs Terror' – is on a Government list of the most dangerous British recruiters for IS.
Since Hussain's death, Cyber Caliphate, which briefly took control of a Pentagon-owned Twitter account in January, has kept a low online profile.
But having spent several months apparently harvesting sensitive data, it reappeared on Twitter at just after 9pm last Sunday. 'We are back,' it declared in an opening tweet.
Its Twitter page featured the hackers' nicknames and sinister avatars and the words: 'Islamic State Hackers' in bold red letters. It went on to taunt the West, saying: 'We need years to publish what we have' and adding: 'We will raise our flag in the heart of Europe.'
Then it tweeted a link to the database of stolen Twitter accounts, saying they included details of members of the Saudi royal family, although this could not be verified.
Shortly after 11pm – having thought to have been contacted by a security agency – Twitter suspended Cyber Caliphate's account. It was not immediately clear how the hacked accounts were used. Victims contacted by The Mail on Sunday were unaware they had been hacked. 'Yes, that's my password,' said one, a doctor. 'It's shocking and worrying how they got my details.' The doctor said he had not been warned about the cyber attack by Twitter.
Cyber security expert Tony McDowell said: 'It is very worrying that terrorists are gathering data in this way.'
A Twitter spokesman referred the MoS to its company 'policy' which states: 'Posting another person's private and confidential information is a violation of the Twitter Rules.
'Users may not make threats of violence or promote violence, including threatening or promoting terrorism.' Earlier this year an investigation by GCHQ found that jihadis had targeted email information held by some of David Cameron's most senior Ministers, including Theresa May, the Home Secretary. It is understood that no security breaches occurred.
Last Sunday's incident came as the Government announced that the internet activity of everyone in Britain will have to be stored for a year under new surveillance laws. Mrs May said police and intelligence officers will be able to see the names of sites people have visited without a warrant, in order to fight crime and terror.
By Ian Gallagher
© Associated Newspapers Ltd.