Web-based lending exchange LendingTree, which generates leads in the mortgage business by accepting online customer information, Monday disclosed that it believes several former employees illicitly helped a handful of mortgage lenders gain access to customer data.

"Recently, LendingTree learned that several former employees may have helped a handful of mortgage lenders gain access to LendingTree's customer information by sharing confidential passwords with the lenders," LendingTree stated in a letter sent April 21 to its customers. "When we learned of this situation, we quickly contacted the authorities, and LendingTree is helping with the investigation. We promptly made several system-security changes. We also brought lawsuits against those involved."

LendingTree spokeswoman Allison Vail acknowledged the letter had been sent to customers, but declined to provide further details, such as how many customers would be affected.

LendingTree believes the lenders gained illicit entry to its data systems to access LendingTree's loan-request forms between October 2006 and early 2008. The Charlotte, N.C.-based firm stated that the loan-request forms contained such customer data as name, address, e-mail address, telephone number, Social Security Number, income and employment information.

LendingTree said it is not aware of identity theft or fraudulent activity resulting from the breach.