A 15-year-old Waldorf whiz kid has been charged with obtaining $2,000 worth of computer equipment by using credit card numbers that Secret Service and Maryland State Police officials said he found by linking his home computer to an electronic bulletin board. The bulletin board listed account data lifted from credit card carbons discarded in the Washington area, the police said yesterday.

The youth was charged Feb. 11 with seven counts of theft after authorities were alerted that several boxes of the computer equipment had been delivered to a vacant house. Police said the youth would order the equipment using the false address, and pick up the packages after they were left at the doorstep.

The case underscores a darker side of the computer age, that credit cards numbers -- the staples of today's economy -- can be stolen and passed to thieves anywhere without the card ever leaving the card holder's possession. Goods can then be ordered over the telephone and charged, using the name and account number of the unknowing card holder, police explained.

"There's a lesson to be learned here -- even I started taking my carbons with me," Maryland State Police Sgt. Steven Rupart said yesterday, alluding to the carbon copy impressions of credit cards that carry the holder's name and account number.

"The juvenile had nothing to do with stealing the credit cards -- he would merely kick into this credit card bulletin board. Somebody had stolen the credit card carbons from a dumpster or trash can in different locations in the Washington area," Rupart said.

An electronic bulletin board works much like an old-fashioned cork board used to share information. A computer user dials the number of a computer that contains the information and links his own computer to it through an electronic device called a modem. Within seconds, the two computers are in contact and the caller can read or write messages over phone lines.

Police and the Secret Service are continuing their investigation into the electronic bulletin board used by the Waldorf teen-ager, which they said they believe is being operated in the District and Montgomery, Prince George's and Charles counties. The officials would not disclose details about how the Waldorf youth found the bulletin board, how the board was established or who was operating it.

National and local law enforcement officials said they have not compiled hard statistics on credit card fraud involving computers. But they described the unauthorized invasion of computer systems as a criminal tool that has been increasing along with the use of computers. Losses can be enormous when information such as stolen credit card account numbers is electronically shared through "pirate boards" that broadcast illicitly obtained information.

"Credit card fraud is very lucrative," said Jim Gavin, a Secret Service agent in the Baltimore field office. "If someone steals the credit card from your wallet, that's one thing, but if somebody takes your name and account number and puts it into a so-called pirate board, it takes quantum leaps because that many more people have access to your credit card." The Secret Service assisted state police in the two-week investigation that ended last week with the Waldorf boy's arrest.

Police yesterday said they were alerted to the fraud by the delivery firm. Alarmed that packages from computer companies in seven states had been sent for three months to different names at a vacant house in a small subdivision on the outskirts of Waldorf, United Parcel Service officials called the Secret Service. Police and Secret Service agents dressed as deliverymen dropped off parcels at the house last week. Forty-five minutes later the boy rode up on his bicycle, picked up the package and was arrested, the police said.

"In a matter of seconds your number can go to anybody who has access to a computer or a particular pirate board," Gavin said.

"It's definitely a growing problem. It's almost becoming a crime of opportunity . . . similar to a car that has a key in it that a kid sees and takes."