How to build an inbound email security strategy that meets HIPAA standards

Inbound email remains one of the highest-risk channels for ePHI compromise. An article by Healthcare Innovation, Study: Nearly 7 in 10 Healthcare Orgs Have Compromised Email Credentials, found that 68% of healthcare organizations had compromised email credentials in the dark web analysis. Furthermore, a survey by ITWire found that 77% of healthcare organizations had experienced an email security breach in 2022.

These statistics reveal that healthcare inboxes are under constant attack. Threat actors increasingly target inbound email as the easiest entry point into healthcare networks, leveraging phishing, spoofing, malware, and social engineering to gain access to sensitive systems. Each incoming message represents a potential vector for data theft, ransomware, or unauthorized disclosure of ePHI, all of which can trigger HIPAA violations and costly penalties.

Under the HIPAA Security Rule, covered entities and business associates are required to implement technical safeguards that protect the integrity and confidentiality of ePHI, including information transmitted via email. Yet compliance alone is not enough. True protection requires a comprehensive inbound email security strategy, one that layers advanced encryption, filtering, authentication, and logging mechanisms to stop threats before they reach users.

What is an inbound email security strategy? 

An inbound email security strategy is a structured plan that defines how an organization protects itself from threats delivered through incoming emails, such as phishing, malware, ransomware, spam, and social engineering attacks, while ensuring that legitimate messages are safely received and processed.

In healthcare, where emails often contain electronic protected health information (ePHI), this strategy can help achieve HIPAA compliance. It ensures that inbound communications are not only filtered for security threats but also handled in a way that preserves data confidentiality, integrity, and availability.

Key elements include:

• Filtering and threat detection: Blocks spam, phishing, and malicious attachments before they reach users.
• Encryption: Protects ePHI in transit and at rest, meeting HIPAA’s transmission security standards.
• Authentication: Uses SPF, DKIM, and DMARC to verify senders and prevent spoofing.
• Logging and monitoring: Tracks message flow and supports HIPAA audit control requirements.
• User awareness: Trains employees to identify and report suspicious emails.

Related: What is inbound email security?

Building an inbound email security strategy

When it comes to inbound email, healthcare organizations face a dual challenge: receiving legitimate correspondence that often includes HIPAA-protected health information while simultaneously defending against threats such as phishing, malware, spoofing, and human-error-driven disclosures. An article from HealthTech Magazine, 7 email security strategies to keep patient data safe from evolving cyberattacks, outlines seven strategic building blocks that serve as a robust framework for securing inbound email.

Threat protection at the gateway

The first step is to prevent malicious emails from ever reaching an end user’s inbox. According to the article, you should deploy email-protection tools that perform real-time analysis of incoming messages: scanning for suspicious attachments or URLs, flagging or quarantining high-risk senders, and isolating risky content. 

In practice: implement a secure email gateway (SEG) or cloud-based email filtering solution configured with up-to-date threat intelligence. Set policies so that inbound messages with known bad-sender signatures, high-risk attachments, or suspicious domain names are held for review or blocked before delivery.

Automated encryption of messages containing ePHI

With the HIPAA Security Rule update, encrypting all emails containing PHI provides a ‘safe harbor’ in the event of a breach. 

In practice: configure your system so inbound messages (and attachments) that meet certain criteria (e.g., contain patient identifiers, diagnostic codes, or lab results) trigger automatic encryption. Use transport layer encryption (TLS) and, where feasible, content-level or seamless encryption. Ensure inbound attachments are stored encrypted at rest.

Data loss prevention (DLP) controls

The article emphasizes using DLP tools alongside encryption to identify sensitive content and prevent inappropriate forwarding or external sending of ePHI. 

In practice: create DLP policy filters that scan inbound attachments and email body text for ePHI patterns (patient name + DOB + treatment codes, etc.). Flag or quarantine messages that violate policy (e.g., inbound email containing ePHI being forwarded externally or stored unencrypted). For inbound email, this may also involve detecting unusual destination addresses or recipients not authorized.

See also: What is Paubox data loss prevention?

Comprehensive archiving and retention

HIPAA requires that regulated entities retain certain electronic communications, including emails containing protected health information (PHI), for a duration of six years. This ensures that data is available for audits, legal proceedings, and compliance requirements.

In practice: ensure your inbound email system routes messages into a secure, searchable archive that retains metadata, attachments, and logs for at least the minimum retention period. Make sure the archive is encrypted, access-controlled, and auditable so when inbound emails arrive (especially those containing ePHI), you have both the message and the traceability.

Read more: 

• What is email archiving and retention?
• Defining which emails to retain

Multifactor authentication (MFA) and access controls

Inbound email may carry malicious payloads, but equally dangerous is the inbound email account being hijacked via compromised credentials. The article recommends MFA, a HIPAA Security Rule requirement, to reduce this risk. 

In practice: require MFA for all access to email systems (especially mailboxes receiving inbound ePHI). Use stronger authentication methods like hardware tokens or FIDO2 where possible. Limit access rights to only those users whose roles demand inbound email handling of ePHI. Periodically review account access and disable forwarding to external personal accounts.

Secure file/attachment sharing

Inbound emails often carry attachments, links, or large file transfers (e.g., images, scans, test results), which may bypass standard mailbox size limits and push users toward insecure channels. The HealthTech article recommends secure file-sharing tools integrated with email. 

In practice: implement secure file-sharing portals or add-ons that integrate with the inbound email workflow. When large or sensitive attachments arrive by inbound email, enforce policies, like automatically redirecting attachment retrieval via the portal rather than directly to inboxes, restricting viewing rights, requiring encryption, and logging all downloads. This reduces the risk of ePHI sitting unprotected in users' inboxes.

Learn more: 5 email attachment security best practices

Security awareness training and human-factor defences

Finally, the article emphasizes that technology alone is insufficient; employee training is vital. It states that staff must learn how to recognize phishing, spoofing, and misuse of email, even in inbound contexts. 

In practice: run regular training sessions and phishing simulations focused on inbound email threats (e.g., malicious attachments disguised as referral letters, spoofed sender domains, prompts for urgent action). Encourage users to report suspicious inbound mail. Integrate training outcomes into your monitoring and incident response workflows, and update policies when attack patterns shift.

Integrating Paubox into your strategy

When building an inbound email security strategy, especially one aligned with the Health Insurance Portability and Accountability Act (HIPAA) and handling ePHI, your technical safeguards must not only address filtering, encryption, authentication, and logging but also integrate with existing workflows and platforms. Paubox’s Inbound Email Security solution offers a comprehensive toolset purpose-built for healthcare that can be seamlessly woven into your inbound email security architecture.

Why Paubox is a strategic fit

Paubox’s Inbound Email Security solution is HIPAA compliant by design and built for healthcare organizations, which helps satisfy both regulatory and operational needs. 

The solution integrates with mainstream platforms such as Microsoft 365, Google Workspace, and Microsoft Exchange, reducing deployment friction in organizations that already rely on these environments. 

Its feature set is designed for the high-risk inbound email vector: generative AI threat detection, display-name impersonation protection (ExecProtect+), behavioral analytics, robust quarantine, and logging. 

Read more: Inbound Security: Overview

How to integrate Paubox step-by-step within your inbound email strategy

Baseline configuration and deployment

• Start by subscribing to the Paubox Email Suite Plus or Premium tier, which includes Inbound Email Security. 
• Route your inbound mail flow through Paubox: update your DNS MX records and/or create an inbound gateway in your platform (Google Workspace or Microsoft 365) so the filtering engine handles all inbound traffic. 
• Ensure TLS enforcement and that the Paubox gateway is authorized in your mail flow. This supports the encryption and authentication components of your strategy.

Configure filtering rules and policies

• In the Paubox dashboard, leverage ExecProtect and ExecProtect+ to guard against display-name spoofing and look-alike domains, a common BEC vector in healthcare. 
• Apply block/allow rules, domain management, quarantine settings, and DLP policies within Paubox to align with your inbound workflow (for example: auto-quarantine messages with attachments from unknown domains and allow specific vendor domains to bypass quarantine). 
• Use Paubox’s generative AI engine: it analyzes tone, context, sender behavior, and deviations from historical patterns, helping you detect advanced threats that traditional signature-based filters may miss. 

Align with your encryption, logging, and access-control layers

• While Paubox focuses on threat detection and filtering, ensure your mailbox store, archives, and attachments remain encrypted at rest and in transit, in line with HIPAA §164.312(e). Paubox asserts that patient data is never shared with third parties. 
• Use Paubox’s Mail Log feature: you gain visibility into inbound mails, their categories (Legit, Spam, Phish, ExecProtect, etc.), status (Delivered, Quarantined), and other metadata. This supports monitoring and audit controls per HIPAA technical safeguards (§164.312(b)). 
• Define user access: Paubox allows admin control of quarantines, user self-access (if desired), and configurable autonomy. You should restrict which staff members have rights to release quarantined emails, aligning with role-based access controls. 

Incident response and workflow integration

• When Paubox quarantines a message (e.g., flagged as Phish or ExecProtect), ensure that your incident-response playbook triggers triage, investigation, user notification, documentation, and remediation. Paubox supports transparency by providing reasoning for blocks, aiding your review process. 
• Use the logs and dashboards supplied by Paubox to refine your policies: monitor false positives/negatives, detection trends, and quarantine release patterns. This enables continuous improvement, a key component of your inbound email strategy.

Training, awareness, and policy alignment

• While Paubox delivers strong technical safeguards, employees still need training. Use the platform’s quarantine reports or release workflows to educate users about why certain emails are blocked or quarantined.
• Update your governance policy to reference the use of Paubox as part of your inbound email controls: e.g., specify that inbound email with attachments is routed through Paubox, staff should not bypass Paubox quarantines, etc.
• Periodically review Paubox’s threat logs with your compliance/IT teams to evaluate attack patterns and emerging risks and adjust training content accordingly.

See also: HIPAA Compliant Email: The Definitive Guide (2025 Update)

FAQS

Do inbound and outbound email security differ?

Yes. Inbound security protects against threats entering your organization, while outbound security ensures emails leaving your organization are encrypted and compliant.

Read more: The difference between inbound and outbound email

What are common inbound email threats in healthcare?

Common threats include phishing scams, business email compromise (BEC), ransomware, and spoofed messages impersonating trusted sources. These threats can lead to unauthorized ePHI access or system compromise.

Are free or built-in email filters enough for HIPAA compliance?

Typically, no. Free or default email filters may not meet HIPAA’s strict encryption and auditing requirements. Healthcare organizations need HIPAA compliant email solutions that include business associate agreements (BAAs) and enforce data protection standards.

How can healthcare organizations test the effectiveness of their email security strategy?

Regular penetration testing, phishing simulations, and email system audits can reveal vulnerabilities and measure the performance of current controls, helping organizations strengthen weak points before real threats exploit them.