The biggest data breaches in 2024: 1B stolen records and rising

Executive summary: The report reviews several of 2024's largest cybersecurity incidents — including AT&T call-record leaks, the Change Healthcare/UnitedHealth ransomware theft of sensitive medical and billing records, the Synnovis ransomware attack disrupting UK hospital services, and large data exfiltration from Snowflake customer environments — describing massive data exposures (tens to hundreds of millions of records), widespread operational impacts, and common root causes such as stolen credentials, lack of MFA, and cloud-account compromises.