A security breach in 2022 compromised the data of nearly all of AT&T’s cellular customers, customers of mobile virtual network operators using AT&T’s wireless network, as well as its landline customers interacted with those cellular numbers.
A company investigation determined that compromised data includes files containing AT&T records of calls and texts between May 1, 2022, and Oct. 31, 2022.
AT&T has more than 100 million customers in the U.S. and almost 2.5 million business accounts.
The company said Friday that it has launched an investigation and engaged with cybersecurity experts to understand the nature and scope of the criminal activity.
“The data does not contain the content of calls or texts, personal information such as Social Security numbers, dates of birth, or other personally identifiable information,” AT&T said Friday.
The compromised data also doesn’t include some information typically seen in usage details, such as the time stamp of calls or texts, the company said. The data doesn’t include customer names, but AT&T said that there are often ways, using publicly available online tools, to find the name associated with a specific telephone number.
AT&T said that it currently doesn’t believe that the data is publicly available.
The compromised data also includes records from Jan. 2, 2023, for a very small number of customers. The records identify the telephone numbers an AT&T or MVNO cellular number interacted with during these periods. For a subset of records, one or more cell site identification number(s) associated with the interactions are also included.
The company continues to cooperate with law enforcement on the incident and that it understands that at least one person has been apprehended so far.
Shares of AT&T Inc., based in Dallas, fell more than 2% before the markets opened on Friday.