Causes and prevention strategies for healthcare email breaches in 2026

In 2025, healthcare organizations reported 170 email-related breaches to the U.S. Department of Health and Human Services (HHS). These breaches affected more than 2.5 million individuals and showed that healthcare email security remains vulnerable. Analyzing the root causes and prevention approaches can help organizations limit exposure of protected health information (PHI).

Common causes of healthcare email breaches

Email breaches in healthcare typically fall into three main categories:

• Mailbox takeover via credential theft: Phishing attacks that steal user credentials to access email accounts. These incidents made up around 17% of email breaches and affected over 630,000 individuals. Attackers use compromised accounts to extract sensitive data or send malicious emails.

• Executive and vendor impersonation: Business email compromise (BEC) attacks exploit trusted identities such as executives or vendors. These attacks rely primarily on social engineering to trick recipients into sharing information or transferring funds, often without malicious software.

• Third-party or vendor email exposure: Accidental or improper handling of PHI by business associates or vendors through email. This was the most common type in 2025, accounting for 28% of email incidents.

These breach types share a pattern of abusing trusted channels and identities. This makes malicious activity harder to detect and easier to scale. Overreliance on user vigilance and inconsistent technical safeguards contribute to these security gaps.

Challenges facing healthcare email security

Several persistent factors contribute to ongoing email security issues in healthcare:

• Dependence on user judgment: Many defenses expect users to recognize and respond to suspicious emails. This approach leaves room for process errors and human mistakes.

• Limited behavioral monitoring: Insufficient detection of unusual email behaviors, such as spoofing or lookalike domains, enables attackers to misuse trusted identities.

• Inconsistent encryption practices: Without enforced encryption when sending emails, PHI may be exposed as messages pass through various third parties with differing security measures.

• Reliance on business associate agreements (BAAs): While legal agreements are required, they do not replace strong technical protections for PHI in email communications.

The importance of upstream prevention

Reducing email risks requires stopping threats before they arrive in user inboxes. Prevention at the email gateway is a foundational step. Key techniques include:

• Phishing and impersonation detection: Identifying and blocking attempts to steal credentials or impersonate trusted roles prior to delivery.

• Behavioral analysis: Monitoring email traffic for abnormal patterns that can indicate compromise or impersonation.

Paubox applies protection at the source, securing emails before PHI leaves the sender’s control. This approach does not rely on recipient or vendor email settings and enforces encryption on all outbound messages containing sensitive information.

Targeted safeguards for high-risk users

Executives, administrators, and vendor-facing staff are disproportionately targeted because their identities carry built-in trust. Broad, one-size-fits-all email controls are often not enough.

Organizations reduce risk by applying additional protections to high-risk identities, including:

• Enhanced impersonation detection that focuses on executive names, titles, and trusted vendor identities most often abused in BEC attacks
• Stronger account protections, such as MFA, to limit the impact of stolen credentials and prevent mailbox takeover
• Automatic email protection policies that apply encryption and safeguards without requiring user action

Tools designed specifically to protect high-risk users, such as ExecProtect+, help address the reality that not all inboxes carry the same level of risk.

By concentrating protections where attackers focus their efforts, organizations can meaningfully reduce the likelihood and impact of business email compromise.

Enforcing encryption at the point of sending

Encryption protects PHI in email but often depends on inconsistent vendor or recipient configurations. Enforcing encryption on the sender’s side addresses risks such as:

• Varied security postures of third parties

• Recipient challenges in securely decrypting messages

• Unintended forwarding or exposure after delivery

Paubox seamlessly encrypts all outbound emails, not just those containing PHI, to support HIPAA compliance and reduce risks after messages are sent.

Healthcare email breaches remain a challenge when defensive efforts depend on reactive measures or user action. Stopping threats upstream, applying targeted protection for high-risk users, and enforcing encryption at sending offer practical ways to reduce exposure.

Organizations seeking detailed guidance on securing healthcare email can read the full report The top 3 healthcare email attacks in 2025 and how to defend against them or talk to our team about risk-reduction strategies.