Proton Warns of 300 Million Stolen Login Details Circulating on Dark Web

Proton has issued a warning that 300 million stolen login credentials are actively circulating on the dark web. Through its Data Breach Observatory initiative, Proton is directly monitoring underground cybercriminal forums to identify and report data leaks in real time, helping businesses protect themselves before massive security incidents become public knowledge.

The company’s findings show breaches affecting telecommunications giants, financial institutions, technology firms and transportation services across multiple continents, including Qantas Airways with 11.8 million records exposed in October 2025, Allianz Life with more than one million records, and Tracelo with 1.4 million records leaked. Proton emphasises that four in five small businesses have experienced recent data breaches, with single incidents potentially costing firms over one million dollars.

The data exposed typically includes names, dates of birth, addresses, phone numbers, email addresses, and passwords, with some cases involving social security numbers, banking details, and IBAN information. The warnings come as Proton encourages organisations to monitor for compromised credentials and to reset passwords promptly when breaches are discovered. 3 November 2025.