China Military Unit 'Behind Hacking'

A secretive branch of China's military is most likely one of the world's "most prolific cyber espionage groups", a US cyber security firm has said.

Mandiant said Unit 61398 was believed to have "systematically stolen hundreds of terab ytes of data" from at least 141 organisations around the world.

It traced the attacks to the doorstep of a non-descript building in Shanghai used by the unit, reports the BBC.

China denied hacking and questioned the validity of Mandiant's report.

"Hacking attacks are transnational and anonymous," said foreign ministry spokesman Hong Lei.

"Determining their origins are extremely difficult. We don't know how the evidence in this so-called report can be tenable.

"Arbitrary criticism based on rudimentary data is irresponsible, unprofessional and not helpful in resolving the issue."

Hong added that Beijing "firmly opposes hacking", has taken steps to prevent it and is also a victim of cyber attacks.

In its unusually detailed report, US-based computer security company Mandiant said it had investigated hundreds of data breaches since 2004, most of which it attributed to what it termed "Advanced Persistent Threat" actors.

The details it had uncovered, it said, "convince us that the groups conducting these activities are based primarily in China and that the Chinese government is aware of them".

The most prolific of these actors is APT1, which Mandiant says it "a single organisation of operators that has conducted a cyber espionage campaign against a broad range of victims since at least 2006".

"From our observations, it is one of the most prolific cyber espionage groups in terms of the sheer quantity of information stolen," it said, adding that it was "likely government-sponsored and one of the most persistent of China's cyber threat actors".

"We believe that APT1 is able to wage such a long-running and extensive cyber espionage campaign in large part because it receives direct government support," said Mandiant.