A fake ‘Murdoch dead’ news report, placed on newspaper The Sun’s website during a hacking attack last night by Lulz Security, has prompted a massive IT security crackdown at parent company News International.

Computerworld UK.com has learned that the hackers injected a preformatted HTML file into an old internal server at News International, which is used to serve a text entry window on screen in the company's content management system. The window appears within pages hosted by the paper’s main Amazon Cloud-delivered site, though sources close to News International said the Amazon Cloud data centre was not hacked.

Rupert Murdoch and his son James, as well as former editor Rebekah Brooks, are due to appear at 2.30pm today in front of the Commons Culture, Media and Sport Committee. They will be asked tough questions on allegations that journalists at the company hacked into the voicemail accounts of 9/11 victims, murdered teenager Milly Dowler, and a raft of celebrities, in a bid to find stories.

The spoof story placed last night on thesun.co.uk claimed that Rupert Murdoch had been found dead in his garden. Readers clicking on the hoax story were redirected to new-times.co.uk, where the story was placed, headlined ‘Media mogul’s body discovered’. The spoof story claimed Murdoch had taken palladium, a radioactive substance.

The news has prompted an aggressive IT security clampdown at News International this morning.

Sources told Computerworld UK.com that News International’s staff have been issued with new login and password details, following the hacking attack, and that the company has also shut off remote access to its systems.

News International operates a Citrix virtual desktop system, which allows staff to ‘hotdesk’ and access their desktop on any PC in the firm's offices. Access codes for the virtual desktop, as well as News International’s content management system, are said to have been changed.

The Sun and The Times websites are back online, but the News International website was offline at the time of writing. News International declined to comment on how it was hacked, what was happening with its corporate website, or how it is tackling IT security concerns. It gave confirmation only that its newspaper sites were back online.

The news comes as The Guardian newspaper reported that police are examining a laptop dumped near former News of the World and Sun editor Rebekah Brooks’ flat in Chelsea. Brooks’ husband, Charlie, has claimed it is his and that it was in a bag accidentally thrown out by a cleaner, but this remains unconfirmed. Rebekah Brooks was arrested on Sunday on suspicion of conspiring to intercept communications, and she was bailed the next day.

Rupert Murdoch, who is accustomed to his journalists writing stories on celebrities and other public figures, has in recent weeks found himself at the centre of the news as the hacking scandal grows.

Another of Scotland Yard’s most senior police officers, John Yates, resigned yesterday. Yates decided in 2009 that there was no need to reopen investigations into alleged phone hacking by journalists on the now-shuttered News of the World newspaper. Yates was about to be suspended.