An investigation has revealed that personal data of some 73 million AT&T customers ended up on the dark web. How the data got there remains a mystery for now. AT&T has launched an extensive investigation in which it is being assisted by outside cybersecurity experts. The U.S. telecom company reports this in a press release.
According to AT&T, it involves 7.6 million people who are currently customers of the company and 65.4 million former customers. Among them, names, dates of birth, address information, email addresses, phone numbers and citizen service numbers have ended up on the dark web. The telecom provider believes the data set is from 2019 or earlier, but that is part of the investigation.
AT&T says there is no evidence that unauthorized persons had unauthorized access to the internal company network. So how the perpetrators were able to obtain the database of private data is as yet unknown. Possibly the data came from one of the vendors AT&T does business with.
Together with external security experts, the company launched an investigation into the facts. It says the incident had "no material impact" on business operations. The telecom company advises customers to reset their passwords. Customers who use the same password in other places online are entirely wise to change them.
The data breach came to light two weeks ago. TechCrunch writes that AT&T notified the first customers of the incident a week ago. The tech site knew about it, but deliberately waited to publish the article so that customers and the telecom company had enough time to take action.
For the beginning of the data breach, we have to go back a few years. In 2019, a hacker claimed to have stolen data on 73 million of the telecom company's customers. AT&T denied at the time that its internal systems had been hacked.
Two years after the data theft, the hacker who claimed the attack published some of the captured data online. Even then, AT&T denied that any data had been stolen. Now, for the first time, all of the stolen data has been made public.
Australian security expert Troy Hunt added the disclosed data to Have I Been Pwned.
With more than 290 million customers, AT&T is the largest telecommunications company in the United States.
