UK telecoms giant TalkTalk is investigating a customer data breach after a hacker, using the alias “b0nd,” claimed to have stolen the personal information of millions of subscribers.
The hacker, posting on a cybercrime forum, alleges the theft of data from over 18.8 million current and former TalkTalk customers. This purportedly includes names, email addresses, IP addresses, phone numbers, and subscriber PINs, which the threat actor is attempting to sell.
TalkTalk spokesperson Liz Holloway confirmed the investigation, but strongly disputed the hacker’s claim of 18.8 million affected accounts, calling the figure “wholly inaccurate and very significantly overstated.”
TechCrunch reports that TalkTalk currently has approximately 2.4 million customers.
“As part of our regular security monitoring, given our ongoing focus on protecting customers’ personal data, we were made aware of unexpected access to, and misuse of, one of our third-party suppliers’ systems. Our Security Incident Response team are continuing to work with the supplier regarding this matter and protective containment steps were taken immediately.” Holloway stated.
The suspected source of the breach appears to be CSG’s Ascendon platform, used by TalkTalk for subscription management. Screenshots shared by the hacker suggest this as the point of compromise.
CSG spokesperson Kristine Østergaard confirmed that an “external party gained unauthorized access to a single provider’s data residing on a CSG platform” on January 21st. However, CSG maintains it has “no evidence” its systems were compromised or that it caused the TalkTalk breach.
TalkTalk confirmed that only a small subset of customer details was stored within Ascendon and that “no billing or financial information was stored on this system.”
The TalkTalk data breach follows a 2015 incident where the company was fined £400,000 after hackers stole the personal data of 157,000 customers, including financial information.
The UK’s Information Commissioner criticized TalkTalk’s inadequate cybersecurity measures at the time. The ongoing investigation into this TalkTalk data breach and theft of customer data continues.