T-Mobile’s cybersecurity team is once again being put to the test. On Monday, the phone carrier announced that it experienced its fourth data breach in three years.
The company did not say what portion of its nearly 100 million user accounts were at risk, but it did confirm that the data accessed did not include names on the account, physical or email addresses, financial data, credit card information, social security numbers, tax IDs, passwords, or PINs.
“Our Cybersecurity team recently discovered and shut down malicious, unauthorized access to some information related to your T-Mobile account,” said Matt Staneff, the Chief Marketing Officer of T-Mobile USA.
“We immediately started an investigation, with assistance from leading cybersecurity forensics experts, to determine what happened and what information was involved. We also immediately reported this matter to federal law enforcement and are now in the process of notifying impacted customers.”
In a letter to customers, Staneff said T-Mobile’s cybersecurity team detected -- then shut down -- “malicious, unauthorized access” to “some” information related to T-Mobile accounts. Staneff qualified “some” as customer proprietary network information (CPNI). Collecting CPNI data is a permission given to phone companies by the Federal Communications Commission (FCC) and typically includes call information like the date, duration of the call, the phone number called, and the type of network a consumer subscribes to -- in short, the type of information that appears on a customer's phone bill.
“We immediately started an investigation, with assistance from leading cybersecurity forensics experts, to determine what happened and what information was involved. We also immediately reported this matter to federal law enforcement and are now in the process of notifying impacted customers,” Staneff said.
T-Mobile users weren’t so lucky in March 2020 when a data breach allowed hackers to gain access to T-Mobile employee email accounts. That, in turn, opened up access to customers’ names, addresses, Social Security numbers, financial account information, phone numbers, billing and account information, and rate plans.
T-Mobile offers to answer any questions
Staneff said the company is ready to answer additional questions if a customer wants further details. Customers can either contact the company online, ask questions at one of the company’s stores, or go through the customer service team at 1-800-937-8997.
“We are sorry for any inconvenience this may cause you. We take the security of customer information seriously and, while we have a number of safeguards in place to protect customer information from unauthorized access, we will continue to work to further enhance security so we can mitigate this type of activity,” Staneff promised.