AT&T on Saturday said that data on roughly 73 million current and former customers was exposed on the dark web, including social security numbers and other personal information. AT&T used the Easter holiday weekend to quietly share details on data that surfaced on the dark web roughly two weeks ago.

It is not yet known whether the data in those fields originated from AT&T or one of its vendors. With respect to the balance of the data set, which includes personal information, the source of the data is still being assessed.

The company said a “robust investigation” investigation is underway, supported by internal and external cybersecurity teams. Read more about this story on our LinkedIn page