Christopher Painter, deputy chief of the computer crimes and intellectual-property section at the U.S. Department of Justice, said there had been a distinct shift in recent years in the type of cybercriminals that online detectives now encounter.
"There has been a change in the people who attack computer networks, away from the 'bragging hacker' (and) toward those driven by monetary motives," Painter told Reuters in an interview this week.
Although media reports often focus on stories about teenage hackers tracked down in their bedroom, the greater danger lies in the more anonymous virtual interlopers.
"There are still instances of these 'lone gunman' hackers, but more and more, we are seeing organized criminal groups, groups that are often organized online, targeting victims via the Internet," said Painter, in London for a cybercrime conference.
Typically, these groups engage in, carding (the illegal use of bank cards) and so-called , where hundreds and sometimes thousands of computers are taken over and used to infect other machines.
Precise figures on the global cost of online crimes are hard to pin down, in part because some organizations prefer to keep quiet rather than publicize that their networks have been successfully attacked.
In other cases, companies and individuals are unaware that they have been defrauded.
The FBI estimates that all types of computer crime in the United States cost industry about $400 billion, while in Britain, the Department of Trade and Industry said computer crime had risen by 50 percent over the last two years.
"Because crimes are committed online, a lot of people still don't understand what is happening," Painter said.
A growing worry is that cybercrooks could target emergency services for extortion purposes or thatlike water and electricity.
Painter said there was a recent case in the United States in which two young hackers inadvertently switched off all the lights at the local airport.
"There is no question the threats are varied, and the perpetrators are more sophisticated," he said. "On the upside, the response is also getting better."
Transborder cooperation on Internet crime was improving with a number of large multicountry raids, demonstrating that national enforcement agencies can work well together.
Painter said better detection and more successful prosecutions also needed to be mirrored by appropriate sentencing.
"In the United States, certainly, sentencing has become more significant in the recognition of the seriousness of Internet crime."
He said hackers were being viewed less as "playful villains," while organized cybercriminals were being hunted with the same vigor as physical crooks.