YOKOSUKA NAVAL BASE, Japan – A credit card hacking operation has now victimized at least 330 customers of Chili’s restaurant on Yokosuka Naval Base, Navy officials said Monday.

The 330 victims have reported an estimated $190,000 in fraudulent charges to the Naval Criminal Investigative Service since the investigation began Oct. 4.

That number is expected to climb, since some of the restaurant’s patrons might have not yet been victimized, or might have reported fraudulent charges solely to their banks and credit unions, officials said.

NCIS and private bank officials continue to investigate the hacking of the restaurant’s credit card server, which Chili’s officials said occurred “somewhere most likely outside of Japan” in a statement earlier this month.

Although it remains unclear exactly when the attack occurred, Yokosuka patrons were already reporting cases of unexplained credit card charges in September.

During the past week, new fraudulent charges continued to pop up on customers’ statements.

“Patrons are reminded to continue to monitor their credit card activities closely and to make sure that any case of credit card fraud is brought to the attention of your bank and NCIS as soon as possible,” base spokeswoman Michelle Stewart said in a statement Monday.

According to a Nov. 4 statement, Chili’s Yokosuka said they would be “installing a new system with increased security measures to further protect our guests from future credit card fraud.”

Chili’s is not accepting credit cards until the system is installed, according to the restaurant.

Sophisticated credit card fraud has become simpler in recent years with the rise of Internet “carding forums,” which facilitate the sale of stolen credit card numbers in bulk. Scammers then use relatively inexpensive machines to imprint the numbers on new plastic cards.

For example, an Indiana man was sentenced to 14 years in prison in U.S. District Court in September after using carding forums and equipment to manufacture 21,000 credit cards and accrue $3 million in fraudulent charges, according to a statement from the U.S. Attorney’s Eastern Virginia District Office.

Tony Perez III, 21, said he also sold card numbers to other scammers through online businesses, according to the statement.

Sign Up for Daily Headlines

Sign up to receive a daily email of today's top military news stories from Stars and Stripes and top news outlets from around the world.

Sign Up Now