WASHINGTON — T-Mobile says it has notified nearly all of the millions of customers whose personal data was accessed in a data breach last week.
In a statement Friday, CEO Mike Sievert called the last two weeks "humbling for all of us," adding that he was "truly sorry" and that the company "didn’t live up to the expectations we have for ourselves to protect our customers."
Last week, the company confirmed that personal information from about 7.8 million of its current postpaid customers, 850,000 prepaid customers and more than 40 million credit applicants had been accessed.
Some of that data included Social Security numbers, birth dates, names and driver's license information, but T-Mobile said it did not appear any customer credit card or payment info was leaked.
"Importantly, no phone numbers, account numbers, PINs, passwords, or financial information were compromised in any of these files of [postpaid] customers or prospective customers," T-Mobile said in an update posted online.
In its announcement Friday, T-Mobile added that it now knows how the hacker gained access to customer information and has closed those points of entry, but couldn't elaborate further because of the active investigation.
"In short, this individual’s intent was to break in and steal data, and they succeeded," Sievert wrote.
In addition to contacting those who the company believes had their information compromised, T-Mobile says it will also notify customers whose information they don't believe was accessed via a banner on the company's customer log-in page.
T-Mobile also says it's partnering with two cybersecurity firms, to prevent similar attacks like this in the future.
The Associated Press contributed to this report.