Security Experts:

Hackers Accessed Information of T-Mobile Prepaid Customers

T-Mobile informed some prepaid customers this week that their personal information may have been compromised as a result of a hacker attack.

The company said it recently noticed unauthorized access to some prepaid wireless accounts. These accounts can store names, billing addresses, phone numbers, account numbers, and details about the customer’s mobile plans and features (e.g. whether they use an international calling feature).

This last piece of information represents customer proprietary network information (CPNI) under rules of the U.S. Federal Communications Commission (FCC), which is why the company is required to notify impacted individuals. The telecoms firm has also informed authorities of the incident.

T-Mobile says the incident did not involve any financial information (such as payment card data), social security numbers, or passwords.

Impacted customers have been notified via SMS and they have been urged to confirm or update their PIN on their T-Mobile account for extra protection.

No details have been disclosed about the attack itself and it’s unclear how many customers have been impacted. However, given that T-Mobile has millions of prepaid customers, even a small percentage could mean a significant number of victims.

The disclosure of this incident comes roughly one year after T-Mobile admitted that it had suffered a data breach impacting over 2 million customers. That attack also resulted in personal information getting accessed by hackers.

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.