Experian Gets Hacked, Exposing SSNs, Data From 15 Million T-Mobile Customers

Credit monitoring firm Experian North America yesterday announced that one of its servers had been breached and personal information of some 15 million T-Mobile USA customers had been exposed, including names, dates of birth, addresses, Social Security numbers, and other forms of identification.

Among the victims were new applicants for T-Mobile services who were undergoing a credit check. The encryption for the SSNs and other ID information may have been compromised, according to T-Mobile.

"The investigation is ongoing, but what we know right now is that the hacker acquired the records of approximately 15 million people, including new applicants requiring a credit check for service or device financing from September 1, 2013 through September 16, 2015," said T-Mobile CEO John Legere in a statement to customers. "These records include information such as name, address and birthdate as well as encrypted fields with Social Security number and ID number (such as driver’s license or passport number), and additional information used in T-Mobile’s own credit assessment. Experian has determined that this encryption may have been compromised. We are working with Experian to take protective steps for all of these consumers as quickly as possible."

No payment card or banking information was stolen, according to Experian.

This is the second major data breach suffered by Experian. SSNs of some 200 million customers in the US were exposed in a hack affecting Court Ventures, which Experian acquired in 2012. The attack on Court Ventures reportedly occurred prior to Experian's purchase of the firm.

"Wireless carriers have long been a hot target for hackers due to the wealth of information they store on their customers. It should not be a surprise that we see cybercriminals targeting business partners they can prove to be easier targets than the carrier themselves," says Ken Westin, senior security analyst at Tripwire. "This should be a wake-up call for the carriers and their business partners to be on guard as we usually see these types of attacks occur in clusters within a given industry."

But some experts say that in the end, the blame lies with T-Mobile. "T-Mobile is ultimately responsible for protecting all sensitive data throughout its supply chain and has to rely on the security systems of its downstream partners to protect information. Unless they did a security audit on those partners and are satisfied they will maintain sensitive data in a safe way, they are vulnerable," says Ron Arden, vice president of Fasoo. 

The question now is: what will the attackers do with the valuable personal information. "The information stolen from Experian can be combined with data from other sources and potentially used in sophisticated attacks. It's become commonplace to offer credit monitoring to victims of a data privacy breach, but other attacks could fall outside the monitored time period," says Gord Boyce, CEO of FinalCode, a file security firm. “While there is reference to Experian’s use of encryption for some data, this public disclosure would indicate that personal and identifiable information has, indeed, been exposed. The T-Mobile and Experian relationship illustrates the importance of tracking and auditing the use of sensitive and regulated data in different forms throughout its lifecycle and processing supply chain.

For more information on the breach, read this statement from T-Mobile.