Why Email is Still Healthcare’s Biggest Ransomware Risk

Health systems have spent heavily on cybersecurity over the past five years. Network monitoring, endpoint detection, segmented clinical networks and incident response retainers are now standard line items for most hospital groups. Yet the ransomware attacks that close emergency departments and push clinicians back to paper still tend to start in the same place: a message that looks routine, arriving in a busy inbox.

That’s because email sits at the center of how healthcare actually runs. Referrals, lab results, payer correspondence, vendor invoices and scheduling all move through it. Attackers don’t need to break encryption when they can persuade a billing clerk to open an attachment that looks exactly like last week’s remittance advice. Any serious plan for safeguarding healthcare systems against phishing and ransomware has to start there.

The scale of the email problem

The American Hospital Association’s review of healthcare cybersecurity in 2025 counted 364 hacking incidents reported to HHS by early October, affecting more than 33 million people. That followed a record 2024, when the Change Healthcare attack alone exposed data on 192.7 million individuals. The AHA also found that more than 80% of stolen health data came from third-party vendors and business associates rather than from hospitals themselves.

That last figure matters for email. Vendor and partner accounts are precisely the ones staff trust by default, which is why a compromised supplier mailbox is such an effective way in.

Why phishing still works in clinical settings

Clinicians and administrators work under time pressure, across shifts, often on shared workstations. Messages are expected from labs, insurers, device manufacturers and EHR vendors, so an urgent request with a familiar logo rarely looks out of place. One set of stolen credentials can be enough for an attacker to move from a mailbox into scheduling, billing or file shares.

Attackers know this, and the sector remains a priority target. SonicWall’s 2026 data showed healthcare’s attack volumes fell by less than any other industry it tracks, as covered in this report on why healthcare cyberattacks aren’t falling fast enough.

Hardening email security across the organization

The basics carry more weight than any single product. Multi-factor authentication on every account, phishing-resistant methods for privileged users and strict domain authentication with SPF, DKIM and DMARC remove a large share of easy attacks. Encrypting messages that carry patient information matters too, both in transit and at rest, so a single compromised account doesn’t expose everything it has ever received.

For smaller practices without a dedicated security team, choosing an email service that encrypts by default can close gaps that would otherwise depend on staff remembering to do it manually.

Making reporting quick and blame-free

Someone will click on something they shouldn’t have done eventually. What decides the outcome is how quickly the security team hears about it. A one-click report button, a culture where reporting a mistake is praised rather than punished, and a rehearsed playbook for revoking sessions and resetting credentials can turn a potential outage into a minor incident.

Vendor contracts should also say how fast a business associate will tell you if one of its accounts is compromised.

Treat the inbox as clinical infrastructure

Email is often managed as an office utility. In healthcare it’s closer to clinical infrastructure because when it’s compromised, care slows down. The organisations that recover fastest treat inbox security with the same seriousness they bring to medication safety, with clear procedures, regular drills and a named person accountable for getting it right.