International experts called today for greater cooperation to fight threats to computer networks but they differed on the definition of cyberterrorism, with a top British security official describing it as a "myth".
Estonian defence ministry official Christian-Marc Liflander said sustained electronic attacks on his country last year came both from crude hackers and from sophisticated "cyberterrorists" remotely manipulating zombie computers known as botnets.
"I would say we have entered an era of cyber terror and perhaps even of cyber war," Mr Liflander told a London security conference at the Royal United Services Institute.
Estonia has said it believes the Russian government was behind last year's attacks, which came amid a diplomatic row over Tallinn's decision to relocate a Soviet-era war memorial.
But Mr Liflander said the botnet attacks came from computers in 76 different countries and it was hard to prove who sponsored them. "What we have is just a gazillion IP (Internet Protocol) addresses that don't prove anything."
The effect was to paralyse websites and cause severe disruption to key services such as banking, in a country with one of the highest levels of Internet usage in the world.
But not everyone agrees that "cyberterrorism" is the best way to describe such electronic attacks.
Stephen Cummings, director of the British government's Centre for the Protection of National Infrastructure, said he had seen no evidence to suggest terrorists were bent on using cyberattacks to generate the same devastating impact as their physical attacks.