Cisco boss John Chambers has warned that computer defenders are only a few steps ahead of cyber crooks.

He said that there were few companies or governments that haven't been hacked in the past year. Some of the problem is because lines between home and work lives are blurring, meaning people will increasingly use smart phones, laptop computers and other portable devices outside the control and protection of business settings.

Cloud computing means more sensitive data will be bounced about the Internet and as businesses resort to holding virtual meetings online to save time and money they run risks of competitors or enemies snooping.

He called for more automated technology to protect from attacks. He said that if it requires human intervention, it is too late.