A possible card breach may have occurred at several gift shops and restaurants at a large number of hotels and franchises owned by Hilton Worldwide Holdings, multiple sources in the banking industry have told Brian Krebs, a cyber-security blogger.
Hilton Worldwide said that they are investigating the claims of the breach.
Krebs reported in his blog post that Visa has sent confidential alerts to a lot of financial institutions about a breach at a business between April 21 and July 27 of this year.
Card numbers were included in the alert to the banks, but Visa wasn't able to reveal the business as it goes against the company's policy.
Krebs added in his blog that sources from five different banks say that all the cards mentioned in the alert were used at Hilton properties.
The properties include Embassy Suites, Doubletree, Hampton Inn and Suites, and the Waldorf Astoria Hotels & Resorts.
Sources told Krebs that the hackers have compromised the point-of-sale registers in gift shops and restaurants located at Hilton's hotels and franchise properties.
He adds that the breach did not seem to have compromised the guest reservation system of locations that are affected.
Reuters adds that Hilton Worldwide said last Saturday that they would be investigating the hacking claims.
A spokesman from Hilton said in a statement that they are taking this issue very seriously.
"Unfortunately, the possibility of fraudulent credit card activity is all too common for every company in today's marketplace," the spokesman said. "We take any potential issue very seriously, and we are looking into this matter."
Reuters adds that the spokesman declined to elaborate further on their statement.
Krebs adds in his blog post that it is still not clear how many hotels and franchise properties of Hilton were affected by the hack.
Several sources in the financial industry, though, are saying that the breach may have taken place as early as November of 2014, and it may still be ongoing.
