Paul Dixon, 23, of the Avenue, Seaham, pleaded guilty at Newcastle Crown Court to five offences under the Computer Misuse Act 1990 on the day his trial was due to start today.
Dixon committed denial of service attacks against websites belonging to British Airways, CeX, Police Scotland and Durham Constabulary in October 2014.
A previous hearing at South Tyneside Magistrates’ Court was told the offences were carried out at an address in South Shields.
The court was told then the British Airways website was down for an hour and they estimated their loss as over £100,000 during that period of time. CeX, which sells and buys electronic goods is believed to have lost between £400 and £500. There would have been a serious inconvenience caused to members of the public using the police websites and to the organisations themselves. There would have been no financial gain.
The case was investigated by officers from the cyber crime unit based in NERSOU (North East Regional Special Operations Unit).
DC Greg Hodgson said: “This is a serious crime which has severe consequences to those companies and services who are targeted.”
He added: “Each force in the North-East now has a dedicated cyber crime unit so crimes of this nature can be properly investigated and the offenders brought to justice.”
Judge Stephen Earl told Dixon: "In relation to this matter you have pleaded guilty to all matters, therefore it falls now for you to be sentenced.
"From this moment in time you are subjected to conditional bail and the single condition is that live and sleep each night at your home in Seaham.
"Should you breach these terms or commit a further offence your bail will be removed altogether."
Dixon will be sentenced at 10:30am on May 4.