NEW YORK (AP) — AT&T has informed about 1,600 customers that a rogue employee had accessed account information that might have included Social Security numbers and other personal data.

AT&T says the employee had failed to follow its privacy rules and no longer works for the company.

The company says the employee also might have had access to driver’s license numbers and information about the types of services the customer purchased. AT&T says it’s offering free credit monitoring and has notified federal authorities. A copy of the letter to customers was posted online by Vermont’s Attorney General’s Office.

The August data breach is among the latest disclosed by a major company. Unlike others, though, this one affected a small number of people and resulted from unauthorized access by an insider rather than hacking.

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