For the second time this year, AT&T has fallen victim to a data breach at the hands of its employees.

About 1,600 customers were affected by the August violation, in which an AT&T worker broke the company's privacy policy.

AT&T is sending Vermont-based customers a letter—penned by director of finance and billing operations Michael Chiaramonte and posted to the website of the state's Attorney General—alerting them to the misuse of personal information.

"AT&T's commitments to customer privacy and data security are top priorities, and we take those commitments very seriously," the carrier's letter said. "We recently determined that one of our employees violated our strict privacy and security guidelines by accessing your account without authorization in August 2014."

The employee gained access to account information, including Social Security and driver's license numbers. AT&T did not say if this data has made its way into the hands of scammers, but said that "to the extent that this activity results in any unauthorized charges or changes" to an account, AT&T will not charge you. The company is also offering one year of free credit monitoring with CSID; the letter includes details on how to sign up.

AT&T also suggested customers contact major credit reporting agencies to place a fraud alert on their credit report, and change their current account passcode (or add one, if necessary).

"On behalf of AT&T, please accept my sincere apology for this incident," Chiaramonte wrote. "Simply stated, this is not the way we conduct business, and as a result, this individual no longer works for AT&T."

Federal authorities have also been notified about the incident. The employee in question has been fired.

This news comes days after reports of a summertime cyber attack on JPMorgan Chase, which compromised the personal information of 76 million households and 7 million small businesses—one of the largest data breaches ever. Check out the video below for more.