Is email metadata a risk to HIPAA compliance in email communications?

An NISO primer aiming to break down the complex concept of metadata provides the following simplified definition, “Metadata, the information we create, store, and share to describe things, allows us to interact with these things to obtain the knowledge we need. The classic definition is literal, based on the etymology of the word itself—metadata is ‘data about data.’.” Email metadata refers to the data that accompanies emails but is not part of the main message content itself. While this may seem innocuous or purely functional for the operation of email systems, it can pose privacy and security risks. 

Email systems often retain and route emails with this metadata intact so that healthcare professionals stay apprised of patient communication. It is, however, also filled with identifiers and sensitive information embedded in message headers that need to be removed prior to analysis. 

This data is visible to email servers and intermediaries and cannot be easily encrypted along with the email body for the system to function properly. The leakage of metadata allows attackers or unauthorized parties to piece together a detailed behavioral profile of the sender or recipient, their communication patterns, locations, and even organizational structure.

Understanding email metadata 

Email metadata is all the information not commonly seen in an email. The information includes details like the sender and recipient's addresses, the data and time the email was sent, the subject line, and the routing information of the various servers the email travels through. This data assists in the delivery of emails, helping servers determine how to route messages and making sure they reach the intended recipient. 

Despite its usefulness in email routing, the information within email metadata can be used for nefarious purposes. A research paper from eCrime Researchers Summit provides that, “This information can be exploited by hackers, as it often contains insights about communication patterns and relationships, potentially leading to breaches of privacy and security, especially when sensitive data is involved.” 

The components of email metadata 

• Sender email address (From)
• Recipient email address(es) (To, Cc, Bcc)
• Date and time the email was sent
• Subject line of the email
• Message-ID, a unique identifier for the email
• Return-Path or Reply-To address for email replies
• Received headers showing the path the email took through mail servers
• IP addresses of the sending and intermediate servers
• Authentication results (e.g., DKIM, SPF, DMARC signatures)
• MIME version indicating the email format protocol
• Content-Type specifying text/plain, text/html, or attachment types
• User-Agent or email client information used to send the email
  
  

Is email metadata a risk to HIPAA compliance? 

According to an article in the North Dakota Law Review, “Notwithstanding the beneficial purposes of metadata, such data may be hazardous because it is not 'invisible' to everyone, but may inadvertently become viewable or accessible. Additionally, even if the average user does not see the metadata, it is consistently present and easily accessible.”

Email metadata can be compromised or breached in several ways, mainly through interception during transmission, unauthorized access to email servers, or phishing attacks targeting individuals. When an email is sent, its metadata travels alongside the message, making it vulnerable to interception by hackers who can exploit weaknesses in network security. 

If an email server is also inadequately protected or unauthorized personnel gain access, there is the risk that the metadata as well as the email contents, can be retrieved. If the compromised email metadata contains protected health information like the patient's name or treatment information, its exposure could lead to a HIPAA violation. 

The hidden information metadata exposes 

According to a study titled ‘Using Social Metadata in Email Triage: Lessons from the Field’, “Unfortunately, email clients typically ignore this social metadata —the information about both a persons‟ history of interaction with their correspondents, and the ways that a message is addressed.” 

Hidden metadata exposes detailed descriptive, contextual, and personal information embedded within datasets. The existence of metadata fundamentally arises from the need to provide context, structure, and meaning to raw data, enabling effective organization, discovery, retrieval, validation, and reuse. Metadata is designed to make data understandable to both humans and machines by explaining what the data represents, how it was collected, by whom, under what conditions, and with what quality standards. 

This descriptive information ensures the data is findable, interoperable, and reusable according to the FAIR principles: findable, accessible, interoperable, reusable; widely endorsed in scientific data management. Metadata includes standardized vocabularies, ontologies, and classification schemes to maintain consistency and accuracy across datasets and repositories. Without metadata, data would exist as isolated, context-free bits of information, severely limiting their scientific value and delaying discovery.

How does HIPAA compliant email secure email metadata 

Paubox employs automatic encryption of outbound emails, including email metadata, to protect them from interception and unauthorized access while in transit across the internet. This encryption occurs seamlessly in the background without additional steps required by the sender or recipient. It allows metadata such as sender and recipient addresses, timestamps, routing information, and subject lines to be encrypted just like the email body.

Risks like data breaches, interception, and tampering, which are concerns since metadata can contain sensitive identifiers capable of exposing patient and healthcare provider identities. Paubox also uses authentication mechanisms including Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC). These protocols verify that emails are sent from trusted sources and help prevent spoofing and phishing attacks that could compromise metadata integrity.

FAQs

What is encryption? 

It is the process of converting information into a code to prevent unauthorized access. 

What is an IP address? 

A unique string of numbers assigned to each device connected to the internet identifying its location and allowing communication between devices. 

What is phishing?

It is a fraudulent attempt to obtain sensitive information like passwords or credit card details.