WASHINGTON — The victims were their own worst enemies.

The hacking techniques the U.S. government says China used against American companies turned out to be disappointingly mundane, tricking employees into opening email attachments or clicking on innocent-looking website links.

The scariest part might be how successfully the ruses worked. With a mouse click or two, employees at big-name American makers of nuclear and solar technology gave away the keys to their computer networks.

In a 31-count indictment announced on Monday the Justice Department said five Chinese military officials operating under hacker aliases such as “Ugly Gorilla,” “KandyGoo” and “Jack Sun” stole confidential business information, sensitive trade secrets and internal communications for competitive advantage. The U.S. identified the alleged victims as Alcoa World Alumina, Westinghouse, Allegheny Technologies, U.S. Steel, United Steelworkers Union and SolarWorld.

MORE AUSTIN POWERS THAN BOND

China denied it all on Tuesday.

Meanwhile, the Justice Department is spelling out exactly how it says China pulled it off.

The U.S. says the break-ins were more Austin Powers than James Bond. In some cases, the government says, the hackers used “spear-phishing” – a well-known scam to trick specific companies or employees into infecting their own computers.

The hackers are said to have created a fake email account under the misspelled name of a then-Alcoa director and fooled an employee into opening an email attachment called “agenda.zip,” billed as the agenda to a 2008 shareholders’ meeting. It exposed the company’s network. At another time, a hacker allegedly emailed company employees with a link to what appeared to be a report about industry observations, but the link instead installed malicious software that created a back door into the company’s network.

‘REALISTIC-LOOKING MESSAGES’

“We are so used to solving problems by clicking an email link, looking at the information and forwarding it on,” said Chris Wysopal, a computer security expert and chief technology officer of the software-security firm Veracode. “And if hackers know about you and your company, they can create really realistic-looking messages.”

And use of the rudimentary efforts described doesn’t mean foreign governments and others won’t use more sophisticated and harder-to-detect techniques, said Joshua Corman, the chief technology officer for Sonatype, which helps businesses make their software development secure. Determined hackers escalate their attacks when necessary, he said, but in the cases cited in the federal indictment announced Monday, they didn’t have to escalate very far.

Corman noted that the U.S. has much higher investments in research and intellectual property, making its risk of loss in such thefts disproportionately higher than China’s.