Bloomberg reports in detail on a major hacking operation which targeted top officials and corporations in the E.U. and U.S. and may have links to the Chinese military:

Observed for years by U.S. intelligence, which dubbed it Byzantine Candor, the team of hackers also is known in security circles as the Comment group for its trademark of infiltrating computers using hidden webpage computer code known as “comments.”

During almost two months of monitoring last year, the researchers say they were struck by the sheer scale of the hackers’ work as data bled from one victim after the next: from oilfield services leader Halliburton Co. (HAL) to Washington law firm Wiley Rein LLP; from a Canadian magistrate involved in a sensitive China extradition case to Kolkata-based tobacco and technology conglomerate ITC Ltd. (ITC)

The researchers identified 20 victims in all — many of them organizations with secrets that could give China an edge as it strives to become the world’s largest economy. The targets included lawyers pursuing trade claims against the country’s exporters and an energy company preparing to drill in waters China claims as its own.

“What the general public hears about — stolen credit card numbers, somebody hacked LinkedIn (LNKD) — that’s the tip of the iceberg, the unclassified stuff,” said Shawn Henry, former executive assistant director of the FBI in charge of the agency’s cyber division until leaving earlier this year. “I’ve been circling the iceberg in a submarine. This is the biggest vacuuming up of U.S. proprietary data that we’ve ever seen. It’s a machine.”