AT&T says 'nearly all' of its customers' call and text data has been leaked in massive security breach

'Nearly all' AT&T customers' data was obtained by hackers in one of the biggest data breaches in US history.

The telecoms giant said the call and text records of around 110 million wireless customers were accessed over a five month period in 2022.

Although the exposed data did not include customer names, there are 'publicly available online tools' capable of connecting numbers with people's identities, the company said.

AT&T admitted it had first learned about the hack in April, but is now notifying former and current customers who were impacted.

The exposed data was illegally downloaded from a workspace on a third-party cloud platform, Snowflake, and law enforcement is now investigating. One person has been arrested so far.

The compromised data included records of calls and texts sent between May and October 2022.

The contents of those calls or texts were not accessed, AT&T said, or personal information such as social security numbers.

However, the company noted that the information was enough to identify geographic location of multiple individuals.

The compromised data also included records from January 2, 2023, for a very small number of customers.

AT&T landline customers who interacted with AT&T mobile users during that time were also affected.

A subset of stolen records included one or more cell site identification numbers, which is are unique location-related identifiers linked to specific cell towers.

'At this time, we do not believe that the data is publicly available,' AT&T shared in the Friday announcement.

If the data were to be released, it would reveal communication records of high profile individuals like politicians, executives, activists, journalists and their sources, Bloomberg reported.

The company said it first learned about the data breach on April 19 after a hacker claimed to have unlawfully accessed and copied AT&T call logs.

AT&T 'immediately' hired investigators who found the files were unlawfully exfiltrated between April 14 and April 25.

AT&T said it has taken additional cybersecurity measures including closing off the point of unlawful access.

The company also said the incident has not had a material impact on AT&T's operations.

However, AT&T stock dropped 2.7 per cent in pre-market trading Friday after the telecom firm confirmed the breach.

News of the 2022 hack comes just months after AT&T acknowledged another data leak in March that happened in 2019 or earlier and affected more than 73 million users.

The leaked dataset includes names, home addresses, phone numbers, Social Security numbers, and dates of birth, TechCrunch reported.

However, AT&T had previously denied a breach to its systems weeks before news broke about the hack.

The two data breaches are just part of the telecommunication's woes in recent months that have seen outages across the nation on several occasions.

The largest outage hit in February, leaving more than 70,000 customers without service for 12 hours.

The company blamed the blackout on a 'software glitch' and compensated all of its customers with a $5 credit.