This is according to The T-Mo Report in which they have obtained internal documents in which it appears that the carrier has experienced a small data breach. The documents show that the carrier has noticed unauthorized activity on some customer accounts where the attacker was viewing data like names, addresses, phone numbers, plan rates, and more.
Some also experienced unauthorized SIM swaps, but thankfully after contacting T-Mobile support, they were able to regain access to their SIM cards. T-Mobile has since reached out to these customers to let them know specifically what was or wasn’t viewed, and reassured them that the hackers did not steal any password or payment related data that they are aware of.
What’s disturbing is that this is not the first breach T-Mobile experienced this year. There was another breach dating back in August, but thankfully this time it appears to be less severe.