Healthcare and Public Health (HPH) organizations have been alerted to the growing threat presented by email bombing attacks, a tactic increasingly utilized by cybercriminals to disrupt operations and compromise security. Email bombing, also referred to as mail bomb or letter bomb attacks, involves inundating an email address or server with a large volume of emails in a short period, overwhelming the recipient’s inbox and rendering it unusable. These attacks, categorized as Denial of Service (DoS) attacks, aim to disrupt regular communication channels by flooding them with spam emails, making it challenging for users to access legitimate messages.
The threat of email bombing attacks within the HPH sector is severe, given the need for of timely and secure information exchange in this domain. A notable incident occurred in 2016 when malicious actors orchestrated a massive cyber assault targeting thousands of “dot-gov” (.gov) email inboxes with subscription requests. This onslaught rendered numerous email accounts unusable for extended periods, highlighting the disruptive potential of such attacks. The healthcare sector, in particular, relies heavily on email communication for various purposes, including patient care coordination, administrative tasks, and information sharing among healthcare professionals and organizations. Email bombing attacks employ various techniques to overwhelm email servers and inundate victims with many unwanted emails. One prevalent method is registration bombs, where automated bots search the web for newsletter sign-up pages or forms that lack live-user authentication requirements. Attackers maintain lists of vulnerable websites and use bots to sign up victims for multiple newsletters simultaneously. This flood of emails not only overwhelms the victim’s inbox but also leads to the recipient being added to additional spam, phishing, and malware lists, worsening the impact of the attack. Attackers may also utilize dark web marketplaces to purchase email bombing services, further complicating detection and attribution.
In the event of an email bombing attack, victims are advised to adopt a proactive approach to mitigate the impact and prevent further escalation. It is important that individuals and organizations to refrain from engaging with the attacker, as responding to the bombardment may exacerbate the situation. Users should also exercise caution when interacting with suspicious emails, avoiding clicking on links or opening attachments that could contain malware or malicious payloads. Prompt reporting of the incident to IT or cybersecurity teams enables immediate action to be taken to mitigate the attack and implement additional security measures. To defend against potential email bombing attacks, organizations should implement comprehensive security policies addressing both user behavior and technical processes. User awareness and training programs are important components of educating employees about the risks associated with email bombing and empowering them to recognize and report suspicious emails effectively. Implementing measures such as confirmed opt-in processes and reCAPTCHA can also help verify the authenticity of email sign-ups and prevent automated bots from inundating email servers with spam messages.
Given the persistent threat presented by email bombing attacks and their potential impact on key infrastructure and services, including healthcare delivery, proactive cybersecurity measures are necessary. Healthcare organizations must prioritize cybersecurity initiatives, including conducting regular risk assessments, developing robust incident response plans, and improving network security measures to safeguard against evolving cyber threats. Collaboration with industry partners and government agencies can also facilitate information sharing and best practices exchange to strengthen collective defenses against email bombing and other cyberattacks targeting the healthcare sector.