How email can act as a digital backdoor

Cybercriminals deploy various techniques, particularly phishing, malware, and ransomware, to compromise electronic health records (EHRs) and other critical data. Email can be the entry point whereby attackers send deceptive messages designed to mislead recipients into revealing login credentials or inadvertently downloading malicious payloads. By successfully exploiting email systems, attackers gain unauthorized access to internal networks and sensitive medical data, a hallmark of the “digital backdoor” phenomenon.

The intricate connectivity of medical devices to hospital networks further compounds the threat presented by email-based attacks. Research underscores that many medical technologies, including infusion pumps, insulin devices, and pacemakers, possess inherent cybersecurity vulnerabilities such as unencrypted communication and default hardcoded passwords. 

These weak points, when combined with compromised email access, enable attackers to exert remote control or introduce malware into clinical systems. For example, malware infections impacting devices at the US Department of Veterans Affairs revealed how a single malicious entry via trusted email or network connections can propagate widely, prompting isolation measures that undermine interoperability and healthcare delivery.

The journal article that referenced the Veterans Affairs breach goes on to state, “Such incidents, together with the national Ponemon and SANS research reports, prompted the US Federal Bureau of Investigation (FBI) to investigate health care as a potential high-profile risk, and issued a private industry notification.”

Email’s dominance as the primary communication channel for providers, staff, and patients

A comprehensive cross-European survey involving over 14,000 participants revealed substantial variability in patient use of email for healthcare communication, with a median prevalence that nonetheless underscores widespread adoption. For instance, Denmark reported the highest rate with approximately 50.7% of surveyed individuals having sent or received emails with their healthcare providers, while countries like France had lower rates near 18.7%. 

These findings show the different healthcare infrastructures and cultural attitudes toward digital communication influence usage but confirm that email remains a major conduit for patient-provider interaction across diverse settings. Importantly, the study noted that email communication is positively correlated with poorer self-reported health, multimorbidity, and increased frequency of physician visits, suggesting that patients with more complex or chronic health needs increasingly rely on email to maintain continuous engagement with their care teams.

Email as healthcare’s weakest security link

Hacking and IT incidents are the most common causes of breaches, with email and network servers being among the most frequently targeted systems over ten years. A Healthcare study titled ‘Healthcare Data Breaches: Insights and Implications’ takes a look at the prevalence of cybersecurity incidents in healthcare, “As reported by many practitioners, from 2005 to 2019, the total number of individuals affected by healthcare data breaches was 249.09 million. Out of these, 157.40 million individuals were affected in the last five years alone.”

Exposure to persistent intrusion attempts using methods such as phishing, ransomware, and malware delivery vehicles directly through email communications. Cybercriminals exploit email because it serves as a ubiquitous communication channel inside healthcare organizations, providing a direct pathway to access electronic health records (EHRs) and network infrastructure once users interact with malicious content embedded in emails.

A key human-centered factor that explains email’s vulnerability is the pervasive role of social engineering attacks, especially phishing. Social engineering manipulates healthcare workers, the so-called human firewall, into unwittingly breaching security protocols by revealing credentials or executing malicious links. Unintentional human factors like negligence, carelessness, and falling victim to phishing attacks account for a greater number of healthcare data breaches than malicious intent. 

One grave example noted was a single phishing incident that triggered the largest cybersecurity breach recorded in healthcare, emphasizing the outsized risk posed by human error in email interactions. Despite regulatory efforts such as HIPAA and HITECH that require technical, administrative, and physical safeguards, the lack of human security awareness remains a failure point.

The common attack vectors

• Phishing attacks: Cybercriminals send deceptive emails pretending to be legitimate sources to trick employees into revealing passwords or downloading malware.
• Email spoofing and impersonation: Attackers forge email headers or impersonate executives to authorize fraudulent requests or steal sensitive information.
• Ransomware delivery via email: Malicious attachments or links in emails install ransomware that encrypts healthcare data and demands payment.
• Business Email Compromise (BEC): Attackers gain access to or impersonate legitimate email accounts to conduct fraud, often manipulating financial transactions or confidential data.
• Vendor Email Compromise (VEC): Cybercriminals take over vendor or supplier email accounts and insert themselves into legitimate conversations to trick employees into processing fake invoices or altering bank details.
• Malware distribution: Emails carry malicious software that steals data, disrupts systems, or spreads additional attacks within the network.
• Display name spoofing: Attackers use familiar display names in emails, making fraudulent messages appear trustworthy and bypassing simple filters.
• Spear phishing: Highly targeted phishing emails crafted with personal information to increase the success rates of credential theft or malware deployment.
• Insider threats facilitated by email: Employees inadvertently or maliciously expose sensitive information or credentials through careless handling of emails.

The digital backdoor concept

A backdoor enables attackers to circumvent the usual authentication mechanisms and gain high-level or persistent access to targeted systems. A study on cyber secure mitigation, “The digitization of control systems in CI, which previously operated from electromechanical systems, embeds the vulnerabilities of the digital system.” Unlike overt malware, which may immediately disrupt operations or produce visible symptoms, backdoors are designed to remain stealthy, allowing attackers to establish a foothold for extended periods. These hidden channels facilitate ongoing surveillance and control, providing cybercriminals with the ability to exfiltrate sensitive data, manipulate system behavior, or deploy further malicious payloads at their discretion.

Technically, backdoors can be introduced in multiple ways: by malicious software installed through phishing or exploitation of vulnerabilities, by exploiting poorly configured software, or even intentionally by developers or insiders during software creation or maintenance. Attackers may deploy reverse shell backdoors, which allow remote command execution via network connections hidden in standard ports or encrypted communication channels, evading firewalls and intrusion detection systems. 

More advanced backdoors leverage legitimate system components, for example, through Windows Management Instrumentation (WMI) persistence or DLL hijacking, to blend in with normal system activity and extend their longevity undetected. This modular stealth capacity makes backdoors particularly challenging to detect and eradicate.

Why current healthcare email security falls short

The failure of healthcare email security is the high volume of suspicious and malicious emails that healthcare organizations routinely receive. A study conducted within a National Health Service (NHS) trust in the UK found that 2% to 3% of their email and internet traffic was classified as suspicious or threats, amounting to over 50 million potentially harmful emails annually. 

Despite this deluge, healthcare staff frequently exhibit limited cybersecurity awareness and training, which results in inadequate detection and response to phishing attempts and related threats. The study emphasizes that while increasing cybersecurity cyberhygiene training has improved awareness, ongoing and pervasive education remains critical. 

Despite regulatory requirements, like those under HIPAA, requiring protection of electronic communications containing protected health information (PHI), compliance alone does not ensure robust email security. This is where HIPAA compliant email software solutions like Paubox offer a critical advantage. 

Paubox is designed specifically to meet HIPAA’s stringent privacy and security standards by providing automatic encryption without recipient action needed, and secure email delivery that preserves the integrity and confidentiality of PHI in transit and at rest. Unlike standard email services that require recipients to engage with secure portals or special passwords, Paubox simplifies secure communication through seamless direct inbox delivery while maintaining compliance.

FAQs

What happens when a healthcare organization experiences a cybersecurity incident?

When a healthcare entity experiences a cyberattack it prioritizes maintaining safe patient care while securing and restoring affected systems. Incident response may involve disconnecting impacted systems, forensic investigations, notifying authorities, and phased restoration of services to protect patient data and resume operations.

What kinds of cyberattacks commonly affect healthcare?

Ransomware attacks, phishing campaigns, and unauthorized access to electronic health records are frequent. Attackers may deploy malware that encrypts data and demands payment or steal sensitive patient information, resulting in disruptions to care and regulatory violations.

How does a ransomware attack impact healthcare services?

Ransomware can disable critical systems including phones and scheduling tools, leading to delays, rescheduling of appointments, and temporary communication outages. Recovery is gradual and carefully managed to ensure security before resuming full service.