NEW YORK -- In what one security expert said may be the most serious such intrusion to date, computer hackers have broken into a Pentagon network, stolen software for a military satelite system and threatened to sell it to terrorists.
The hackers, who call themselves "Masters of Downloading/2016216," claim to have broken into the system in October but waited until last week to contact security expert John Vranesevich and tell him about it.
The stolen software coordinates the military's Global Positioning System, which is used to target missiles and also enables troops to pinpoint their positions with extreme accuracy. The system uses dozens of satellites and has been a key component of the U.S. military since the Gulf War.
Defense Department spokeswoman Susan Hansen said the Pentagon's Defense Information Systems Agency is looking into the matter. She said the stolen software does not contain classified information.
However, Gideon Samid, a computer security expert who has done work for the Pentagon, cautioned that most intrusions tend to be far worse than the government acknowledges.
And Vranesevich said the intrusion could be one of the most serious break-ins of a government network to date. Vranesevich was recently involved in tracking the Israeli hacker known as "Analyzer," who broke into Pentagon computer systems in February.
The theft "should concern a lot of people," said Vranesevich, who interviewed the hackers on his Web site. "Most hacks fall into one category: when a group of kids do the cyberspace equivalent of graffiti. This group is in a whole different category."
Vranesevich interviewed them via Internet chat and e-mail, and posted pictures of the stolen software in action on his Web site. The Defense Department confirmed the software was genuine. It was during these interviews that members of the group said they might sell the information.
"I think international terrorist groups would be interested in the data we could gain access to," wrote one member. "Governments would buy it for intelligence purposes."
The information "is very dangerous in the wrong hands," one of the hackers said.
Vranesevich said members of the group range in age from 19 to 28, which makes them older than the average hacker. The group claims to have 15 members -- eight in the United States, five in Britain and two in Russia.