Just before the year ends, T-Mobile encounters another data breach. But as reported, the new breach appears to be smaller in scale compared to the previous attack in August.
The T-Mo Report earlier reported the breach. The report revealed internal documents related to the attack, which showed some “unauthorized activity” on customers’ accounts. The attack was said to involve “viewing of customer proprietary network information (CPNI), an active SIM swap by a malicious actor, or both.”
Customers who are affected by the breach are separated into three categories, as detailed in the document.
“Affected customers fall into one of three categories. First, a customer may have only been affected by a leak of their CPNI. This information may include the billing account name, phone numbers, number of lines on the account, account numbers, and rate plan info. That’s not great, but it’s much less of an impact than the breach back in August had, which leaked customer social security numbers.
The second category an affected customer might fall into is having their SIM swapped. This is where a malicious actor will change the physical SIM card associated with a phone number in order to obtain control of said number. This can, and often does, lead to the victim’s other online accounts being accessed via two-factor authentication codes sent to their phone number. The document says that customers affected by a SIM swap have now had that action reversed.”
The third category involves customers who experienced both having their CPNIs viewed and a SIM card swap.
T-Mobile has not yet released any statement about the report. There is also no information on how big this attack is. But according to our source, affected customers have already been informed about the incident via a letter. T-Mobile
Source: The T-Mo Report
