Credit reporting agency Equifax confirmed "fraudulent and unauthorized access" to the financial files of four high-profile people, but the company declined to identify the individuals.
Equifax confirmed the security breach Tuesday, one day after a website posted what hackers claim to be Social Security numbers, credit reports, former addresses and personal banking information of celebrities and other top Washington, D.C., officials, including first lady Michelle Obama.
"We are aware of recent media reports pertaining to unauthorized access to files belonging to high-profile individuals. Equifax can confirm that fraudulent and unauthorized access to four consumer credit reports has occurred," Tim Klein, a spokesman for Equifax, wrote in a statement Tuesday.
The U.S. Secret Service has launched an investigation into potential hacking of personal information of Mrs. Obama, Vice President Joe Biden and former Secretary of State Hillary Clinton, sources tell ABC News.
The hackers claim to have what appears to be first lady's credit report, Social Security number, previous addresses and phone numbers.
In an exclusive interview with ABC News Tuesday, President Obama confirmed authorities were investigating whether hackers had indeed obtained and posted online financial information belonging to his wife, but he would not say whether the information was authentic.
"We should not be surprised that if we've got hackers that want to dig in and have a lot of resources, that they can access this information," Obama said. "Again, not sure how accurate but ... you've got web sites out there that tell people's credit card info. That's how sophisticated they are."
ABC News is not disclosing the website's name, which appears to originate in Russia because the Internet suffix of the site's web address was originally assigned to the Soviet Union.
The first lady is not the only potential victim. The ominous website claims it also has personal information on FBI director Robert Mueller, U.S. Attorney General Eric Holder and former Alaska Gov. Sarah Palin.
The site's so-called "secret files" claim to reveal everything from how much Kim Kardashian pays for her car lease to Ashton Kutcher's American Express bill and even Paris Hilton's credit score.
Beyonce, Jay Z, Mel Gibson, Britney Spears, Hulk Hogan, Arnold Schwarzenegger and Donald Trump were some of the other celebrities who were allegedly hacked.
Cyber security analysts say the theft of such information can create havoc.
"If they have your credit report, that's all they need to take over your identity," said Marc Swillinger, former federal prosecutor of Justice Department Cybercrimes division.
ABC News' George Stephanopoulos, Abbie Boudreau, Jack Date and Mary Bruce contributed to this report.