Report by Paubox
2025 mid-year email breach data reveals there's no slowing down
Key Findings
The largest single email breach, affecting United Seating and Mobility, exposed over half a million records.
The sharp rise in Microsoft 365 email breaches in healthcare represents a 21% increase year-over-year.
The Episource breach affected 5.4 million individuals
The average healthcare email breach exposed nearly 16,000 individual records in the first half of 2025.
More than 1.6 million patient records were compromised across all analysed email-related healthcare incidents that occurred in the first half of 2025.
Microsoft 365 environments now account for 52% of all healthcare email breaches. This represents a dramatic surge from 43% just one year ago.
Incidents involving Mimecast email customers accounted for 8% in healthcare.
Incidents involving Barracuda email customers accounted for 5% in healthcare.
Incidents involving Proofpoint email customers accounted for 6% in healthcare.
Business associates (including billing vendors, imaging firms, and outsourced IT providers) were involved in 17 of the 107 email-related breaches in healthcare. This represents 16% of all incidents.
41% of healthcare organizations are now classified as high-risk. This compares to just 31% last year.
Cyberattacks are cited as the leading cause of critical workflow disruptions by 50% of healthcare organizations.
79% of breached healthcare organizations have ineffective DMARC protection. This is up dramatically from 65% in 2024.
IT leaders estimate that only 5% of known phishing attacks in healthcare are actually reported by employees to security teams.
81% of healthcare email breaches were classified as hacking or IT incidents.