A self-defined Saudi hacker claimed he had published details of 400,000 Israeli-owned credit cards online, but the card firms on Tuesday insisted that only 14,000 cards had been affected.
Details of the hack were exposed late on Monday in a statement posted on an Israeli sports website.
"Hi, It's 0xOmar from group-xp, largest Wahhabi hacker group of Saudi Arabia," the statement read. "We are anonymous Saudi Arabian hackers. We decided to release first part of our data about Israel."
Links in the statement led to websites containing details of Israeli credit cards, as well as cards used to purchase merchandise from "Judaism" websites and those used to donate to "Israeli Zionist Rabbis."
"Enjoy purchasing stuff for yourself," it said, noting the "fun" in "watching 400,000 people gathered in front of Israeli credit card companies and banks" and "making Israeli credit cards untrustable in the world, like Nigerian credit cards."
Israel David, CEO of Israel Credit Cards-Cal Ltd, confirmed the security breach but said that after combing through details posted online, they had identified only 14,000 valid credit cards.
"These cards are being removed from the system," he told Israel's private Channel 2 television on Tuesday morning.
Isracard CEO Dov Kotler told public radio there was no breach of security at the credit card firms or any banks.
"This was the result of a break-in to Internet sites in Israel," he said.
According to Kotler, the breach is not major considering the fact there are approximately seven million credit cards in use in Israel.
"We are fully in control of this situation," he added.