Allow listing of senders and high confidence phishing were the topics of discussion at the August 2026 Paubox Zoom social mixer. Participants generally agreed that high-confidence phishing should remain blocked even when it comes from an allow-listed sender. They also identified customer-configurable filtering logic as the preferred long-term solution.

Healthcare organizations exchange email with patients, caregivers, labs, pharmacies, health plans, referring physicians, and vendors. An overly strict rule can inadvertently block a legitimate email. An overly broad exception can inadvertently allow a malicious email into the inbox. Configurable inbound email filtering gives authorized administrators the ability to determine how the system should respond to various threat indicators while maintaining critical protections.

 

What is configurable inbound email filtering?

Inbound email filtering involves scanning messages before they reach a user’s inbox. A filter could assess information about the sender, authentication results, content within the message, URLs, attachments, malware signals, and phishing or impersonation clues. Configurability then determines how the system treats that message, whether it is delivered to the inbox, labelled, quarantined, rejected, or blocked.

A National Institute of Standards and Technology (NIST) publication explains that organizations can layer email technologies because there’s no single solution that successfully stops all undesirable messages. Configurability lets healthcare organizations decide how those layers function together. But it should not allow every user to modify security settings. Health organizations can restrict who changes policies and set mandatory policies that users cannot override.

 

Why one filtering policy does not fit every healthcare workflow

Healthcare email contains time-critical referrals, billing forms, appointment reminders, and automated alerts. Legitimate messages may include various attachment types, be routed through third-party applications, or come from unfamiliar infrastructure.

The Paubox social mixer noted that meeting-summary applications, payroll systems, and ticketing programs may send mail from an employee’s display name. It can appear similar to display name spoofing, where a malicious actor pretends to be someone you know but the email address does not match. Rather than turning off impersonation protection for their entire organization, healthcare administrators can create specific rules that allow verified applications to bypass certain checks. They can review the authenticated domain and/or intended path before mail is accepted into the system. Safety features should still evaluate the message body for phishing attempts, malware, suspicious links, and other dangerous traits.

Individual departments also have unique email conventions. HR might receive resumes from unexpected addresses. Billing teams may frequently send attachments to health plans. Top-level executives, finance personnel, and IT admins can be targeted because of their access or influence. Inbound filtering rules can be tailored to accommodate these scenarios while maintaining default protections. The goal is to minimize interruptions and apply tighter settings for high-risk users and processes.

 

What healthcare studies show

A 2019 BMJ Health & Care Informatics study analyzed email and web threats against a single National Health Service hospital trust. The organization received 858,200 emails in one month. Of that total, 18,871 were identified as potential threats. The researchers concluded, “Hospitals receive a significant volume of potentially malicious emails.”

Employees cannot consistently be expected to scrutinize every email and web link without tech-enabled assistance. Configurable inbound filtering can block known threats while moving questionable messages to quarantine for additional review before they interfere with clinical workflows.

Another study published in JAMA Network Open looked at the results from 95 simulated phishing email campaigns conducted at six US-based healthcare organizations. Those simulations comprised 2,971,945 messages sent to employees. End users clicked on 14.2% of the test messages. Researchers found that “Among a sample of US health care institutions that sent phishing simulations, almost 1 in 7 simulated emails sent were clicked on by employees.”

Repeated phishing campaigns were associated with lower odds of clicking on a subsequent message. It may suggest continued value from repeated testing and training. Cybersecurity training, however, should not be the only barrier between an attacker and a healthcare inbox. Researchers published comparisons of generic vs. targeted phishing tests in 2022 DIGITAL HEALTH. The study involved thousands of employees at a large Italian hospital. “The results show that customization of phishing emails makes them much more likely to be acted on.” the researchers concluded. Because attackers can tailor messages to a specific hospital, employee, or timely topic. But configurable inbound email filtering can trigger additional scrutiny based on suspicious display names, reply-to addresses, domains, links, and more.

 

Which inbound controls should be configurable?

Threat severity and message action

Healthcare organizations may want to map risk levels to actions. Known malware, malicious links, and high-confidence phishing emails can be blocked or rejected outright. Ambiguous messages that raise some flags but aren’t overwhelmingly suspicious can be quarantined. Unclassified mail or messages that pose a lower risk can be delivered with a warning.

The differentiation allows granular control without making all protections optional. Sending high confidence threats should still trigger organization wide protections even if the sender is on the allow list.

 

Allow list behavior

An allow list specifies individuals or domains where legitimate mail should be treated favorably. It can keep spam filters from delaying anticipated mail. It shouldn’t act as a universal override for security tools.

As the NIST explains, being on an approved-sender list does not mean every message should be accepted without further checks. Mail from an approved sender may still be inspected for malware and malicious links. Allow listed addresses to be able to bypass certain spam filters. Healthcare organizations may want to retain protections against phishing, malware, malicious links, unsafe attachments, and impersonation. Administrators can assign owners and expiration dates to each exception.

 

Links, attachments, and quarantine

When emails are quarantined, administrators can decide who has permission to review them and approve their delivery. Internal emails that contain links but no attachments might be permissible for end users to review, while external emails with executables are flagged for review by security staff. Reason codes, message previews, search capabilities, and audit trails are all examples of tools that can help reinforce consistent judgment. Time sensitive emails can be routed through a defined escalation process so they can be reviewed and released quickly.

 

How healthcare organizations can configure filters safely

Healthcare organizations can start by recording what departments’ users are expected senders, what their authenticated domains are, which automated platforms they use, what file types they send as attachments, and any time-sensitive operations. Once phishing safety rules account for the routine, security teams can define hard standards for unequivocally identified malware, high confidence phishing, and malicious links. Allowances should be as limited as possible, tied to a written business justification, frequently reviewed, and never permitted to bypass the highest risk categories. Administrators can then track false positives, false negatives, quarantine totals, release frequency, and how long it takes to clear genuine emails. Monitoring these statistics will indicate whether a rule is actually safeguarding users or interfering with their ability to do their jobs. Paubox’s 2026 report on healthcare email security found that 41% of breached organizations had high-risk email configurations in 2025, compared to 31% in 2024. Another Paubox survey data brief showed that 86% of healthcare IT leaders said their existing email security tools create friction in daily workflows.

See also: HIPAA Compliant Email: The Definitive Guide (2026 Update)

 

FAQs

How narrowly should healthcare organizations define exceptions for legitimate systems that repeatedly trigger email filters?

An exception should identify the specific sender, authenticated domain, expected sending route, or business process that requires it. Healthcare organizations should also assign an owner, document the reason, and review or expire the exception regularly.

 

Does Paubox currently offer configurable inbound email security controls?

Yes, Paubox Inbound Email Security includes block and allow rules, custom rulesets, quarantine management, ExecProtect, AI analysis, and other adjustable controls. Paubox’s public documentation does not state that customers can rewrite every underlying phishing or AI classification rule.

 

Can a Paubox allow rule override of a phishing, malware, or ExecProtect classification?

No, Paubox states that an allow rule can permit delivery when a message is classified as spam, but it does not override malware, phishing, or ExecProtect filters.