The FBI and Secret Service are investigating "exposed.su," a mysterious website that popped up earlier this week, containing financial information and other personal data of a list of notable individuals, including First Lady Michelle Obama, Vice President Joe Biden, FBI director Robert Mueller, pop star Beyonce Knowles, rapper Jay-Z, actor Ashton Kutcher and others, according to The Associated Press. At least some of the information listed on the website was reported to be authentic, but the site, which operated under an old Soviet Union top-level domain, has since been taken offline. White House Press Secretary Jay Carney was asked about the website in a briefing today but said he had "no assessments to offer" about the situation, and referred further questions to the Secret Service.

Two of the biggest US credit report companies, Equifax and TransUnion, responded directly to questions about the celebrity financial information appearing on the exposed.su website this afternoon, saying their systems were breached. But what they have shared so far points to someone using social engineering, or relying on identifying information available online and via other channels to impersonate the celebrities. Both companies confirmed to Bloomberg this afternoon that financial information of some of their customers had been fraudulently accessed, though it's unclear if that information is the same that appears on the site, and if so, whether it was posted after the companies were breached, or if information already on the website was used to bypass their credit report fraud detection measures.

TransUnion said fraudsters tricked it into handing over credit report information of customers by impersonating them with "considerable amounts" of their information, such as Social Security Numbers. Equifax also told Reuters it had launched an internal investigation after credit reports for four of its customers were taken without proper authorization through the website annualcreditreport.com. Annualcreditreport.com is managed by Equifax, TransUnion and another credit report company, Experian. We've reached out to Experian to see if the company has been affected and will update when we hear back.