Hackers managed to obtain information from 133,000 user accounts after breaching the system used by U.K. telecommunications company Three to identify which customers are eligible for a device upgrade.
The firm revealed last week that there had been an uptick in attempted phone fraud over the past four weeks, including through burglaries at Three stores and intercepted phone upgrades. In eight cases, the company believes phone upgrades were intercepted using information unlawfully obtained from its upgrade system.
According to Three CEO David Dyson, the attackers accessed information from 133,827 customer accounts via “authorized log-ins.” For 107,000 of these customers, the hackers obtained information such as name, billing data, payment type, Three account number, contract details, and handset type.
The other 26,000 people had their name, date of birth, gender, handset type, contract details, phone number, email address, previous address, marital status and employment status exposed. The company has highlighted that bank details, payment information, passwords or PINs are not affected.
“We believe the primary purpose of this was not to steal customer information but was criminal activity to acquire new handsets fraudulently,” Dyson said. “We are contacting all of these customers today to individually confirm what information has been accessed and directly answer any questions they have. As an additional precaution we have put in place increased security for all these customer accounts.”
Authorities announced that three people from Kent and Manchester have been arrested in connection with the data breach. They have all been released on bail.
Three is not the only major U.K. telecoms company to suffer a data breach. In October 2015, hackers managed to steal the details of nearly 157,000 TalkTalk customers, including personal and, in some cases, financial information.
One year later, the U.K. Information Commissioner’s Office handed TalkTalk a record fine of £400,000 ($510,000) for failing to protect its customers’ personal data.