For example, in 2008 Chinese intruders based in Shanghai and linked to the People’s Liberation Army used a computer document labeled “salary increase — survey and forecast” as bait as part of the sophisticated intrusion scheme that yielded more than 50 megabytes of electronic mail messages and a complete list of user names and passwords from a United States government agency that was not identified.

The cables indicate that the American government has been fighting a pitched battle with intruders who have been clearly identified as using Chinese-language keyboards and physically located in China. In most cases the intruders took great pains to conceal their identities, but occasionally they let their guard down. In one case described in the documents, investigators tracked one of the intruders who was surfing the Web in Taiwan “for personal use.”

The NYT is starting in on a cables dealing with the APT.