Reuters, By Joseph Menn

A small, sophisticated international hacking group was responsible for a widely publicized 2011 spying attack on members of Japan's parliament as well as dozens of previously undisclosed breaches at government agencies and strategic companies in Japan and South Korea, security researchers said.

Researchers at Kaspersky Lab believe they have found a squad of hackers for hire, who contract out to governments and possibly businesses, in contrast to recent reports on hacks said to be carried out by full-time government employees.

"What we have here is the emergence of small groups of cyber-mercenaries available to perform targeted attacks," said Kaspersky's global research director, Costin Raiu, in an interview with Reuters.

"We actually believe they have contracts, and they are interested in fulfilling whatever the contract requirements are," he said. Read more.