Citi Discloses Security Flaw in Its iPhone App

In an incident that highlights the growing security challenges around wireless apps, Citi said its iPhone app accidentally saved information—including account numbers, bill payments and security access codes—in a hidden file on users' iPhones. The information may also have been saved to a user's computer if it had been synched with an iPhone.

The issue affected the approximately 117,600 customers who had registered the iPhone app with Citi since its launch in March 2009, a person familiar with the matter said. The bank doesn't believe any personal data was exposed by the flaw.

"We have no reason to believe that our customers' personal information has been accessed or used inappropriately by anyone," Citi said. Apple acknowledged the issue and encouraged users to download the updated app.