A group of Saudi hackers is claiming to have accessed and published the credit card details of hundreds of thousands of Israelis.
Group-XP - which allies itself with the Anonymous collective - says it gained the data after hacking into a major sports website, One.co.il.
It says it was able to gain the credit card details, personal addresses, names, phone numbers and ID numbers of 400,000 people.
"We daily use these cards to solve our problems, purchasing VPNs, VPSes, softwares, renting GPU clusters, renting cloud servers and much more!" say the hackers.
However, Israeli banks say the number of people affected is far lower than the hackers are claiming. Many of the names on the list are duplicates, they say. Isracard, a unit of Bank Hapoalim, says that only around 14,000 of the credit card numbers are valid.
The hacking group claims on Pastebay that it's also got hold of the social security numbers of a million Israelis and will soon post the information online.
"What's fun for us? Watching 400,000 people gathered in front of Israeli credit card companies and banks, complaining about cards and that they are stolen," crows the group.
"Watching Israeli banks shredding 400,000 credit cards and re-generate new cards (so costly, huh?) Watching people purchasing stuff for theirself using the cards and making Israeli credit cards untrustable in the world, like Nigerian credit cards."
Some of the stolen card data appears to have been used to make internet purchases, but the banks say this misuse has been relatively minor and that these cards have now been blocked. They promise that customers won't be held liable.