Nato governments and the public must wake up to the threat of cyberattacks, which could paralyse a nation far more easily than conventional warfare, experts have warned.
"Cybercrime and cyberespionage are topics that can't be ignored," said Melissa Hathaway, a former US cyber tsar, at a conference in Estonia organised by the trans-Atlantic alliance's IT defence unit.
"Key infrastructure, including power stations, have become vulnerable due to their dependence on Internet connections," Mr Hathaway said.
"There is no national security in the modern world without economic security, and both companies and private citizens should also realise the depth of the problem," she added.
Charlie Miller - a security analyst who launches test assaults on IT systems - underlined that cyberwar is far easier than a conventional attack.
"It would take two years and cost less than $50 million a year to prepare a cyberattack that could paralyse the United States," Mr Miller warned. Such an attack could involve fewer than 600 people working to infect computers, he added.
Estonia is home to a unit known in Nato-parlance as the Cooperative Cyber Defence Centre of Excellence.
Bitter experience taught Estonia - one of the world's most wired nations and a Nato member since 2004 - all about cyberattacks.
The Baltic state of 1.3 million people suffered an assault in 2007 that paralysed key business and government web services for days.It came as Estonian authorities shifted a Soviet-era war memorial from central Tallinn to a cemetery site.
The monument, erected when Moscow took over after World War II, became a flashpoint following independence in 1991 for rallies by Estonia's ethnic-Russian minority.
Estonia blamed Moscow for stoking riots in Tallinn as the memorial was moved, and said the cyberattacks were traced to Russian official servers.
Russia, however, denied involvement.
Despite Estonia's experience, people elsewhere have not woken up, said British defence ministry expert Gloria Craig.
"It's still hard to convince the public that a cyberattack is an attack, when people don't see a smoking gun," Mr Craig said.
"As of now Nato is not prepared for a global cyberattack," she added.
The economic crisis has hit cyberdefence programmes, noted Rex Hughes of London-based think-tank Chatham House.
"IT security has faced drastic cuts, like many other sectors, amid the recession and even Nato is far from ready to step up against global cyberattacks," he said.