New T-Mobile Breach

Summary

T-Mobile discovered a breach in which threat actors gained access to account information and may have used that information to port lines to a different mobile carrier without the user’s authorization in SIM-swapping attacks . Information may include full name, address, email address, account number, Social Security number, customer PIN, account security questions and answers, date of birth, and plan and line information. Since the breach, T-Mobile terminated the unauthorized access, notified impacted users on February 9, 2021, and advised them to review their account information and update account passwords, PINs, and security questions and answers.