Hacker threatens to leak a rumoured huge cache of stolen Telefónica data

• A threat actor claims to have stolen 106GB of sensitive files from Telefónica
• Telefónica says the files were old, stolen from a previous incident
• A sample was shared with the media, with the full batch soon to follow

A cybercriminal is threatening to release more than 100GB of sensitive data stolen from Spanish telecommunications giant Telefónica.

In January 2025, the company suffered a data breach at the hand of the Hellcat ransomware operation. At the time, the group broke into the telco through an internal Jira development and ticketing server.

Among the members of the group is a threat actor with the alias Rey, who said that while Telefónica was addressing one flaw, it created another, giving them 12 hours of uninterrupted data exfiltration. During that time, which Rey claims was in late May 2025, they allegedly stole 106GB of sensitive files, counting more than 380,000 files of internal ...