They operate from a bare apartment on a Chinese island. They are intelligent 20-somethings who seem harmless. But they are hard-core hackers who claim to have gained access to the world's most sensitive sites, including the Pentagon.
In fact, they say they are sometimes paid secretly by the Chinese government -- a claim the Beijing government denies.
"No Web site is one hundred percent safe. There are Web sites with high-level security, but there is always a weakness," says Xiao Chen, the leader of this group.
"Xiao Chen" is his online name. Along with his two colleagues, he does not want to reveal his true identity. The three belong to what some Western experts say is a civilian cyber militia in China, launching attacks on government and private Web sites around the world. Watch hackers' clandestine Chinese operation
If there is a profile of a cyber hacker, these three are straight from central casting -- young and thin, with skin pale from spending too many long nights in front of a computer.
One hacker says he is a former computer operator in the People's Liberation Army; another is a marketing graduate; and Xiao Chen says he is a self-taught programmer.
"First, you must know about the Web site you want to attack. You must know what program it is written with," says Xiao Chen. "There is a saying, 'Know about both yourself and the enemy, and you will be invincible.'"
CNN decided to withhold the address of these hackers' Web site, but Xiao Chen says it has been operating for more than three years, with 10,000 registered users. The site offers tools, articles, news and flash tutorials about hacking.
Private computer experts in the United States from iDefense Security Intelligence, which provides cybersecurity advice to governments and Fortune 500 companies, say the group's site "appears to be an important site in the broader Chinese hacking community."
Arranging a meeting with the hackers took weeks of on-again, off-again e-mail exchanges. When they finally agreed, CNN was told to meet them on the island of Zhoushan, just south of Shanghai and a major port for China's navy.
The apartment has cement floors and almost no furniture. What they do have are three of the latest computers. They are cautious when it comes to naming the Web sites they have hacked.