Email Security

How To Protect Network Users From Malicious Emails

Protecting network users from malicious emails involves implementing a combination of technical controls, user education, and best practices. Here are some steps to enhance email security and mitigate the risk of malicious emails:

  1. Deploy Email Filtering Solutions: Implement robust email filtering solutions, such as spam filters and anti-malware scanners, at the network perimeter to automatically detect and block malicious emails before they reach users’ inboxes.

  2. Use Sender Authentication Protocols: Configure sender authentication protocols such as SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance) to verify the authenticity of incoming emails and detect spoofed or forged sender addresses.

  3. Enable Content Filtering: Employ content filtering mechanisms to scan email content, attachments, and URLs for malicious payloads, phishing attempts, and suspicious links. Content filtering can help identify and quarantine potentially harmful emails before they are delivered to users.

  4. Implement Email Encryption: Utilize email encryption technologies such as Transport Layer Security (TLS) and Secure/Multipurpose Internet Mail Extensions (S/MIME) to protect the confidentiality and integrity of email communications, especially for sensitive or confidential information.

  5. Train Users on Email Security Awareness: Conduct regular security awareness training sessions to educate users about common email-based threats such as phishing, spear-phishing, and social engineering attacks. Teach users how to recognize suspicious emails, avoid clicking on unknown links or attachments, and report any suspicious activity promptly.

  6. Enable Multi-Factor Authentication (MFA): Require users to authenticate using multiple factors (e.g., passwords, biometrics, security tokens) before accessing their email accounts. MFA adds an extra layer of security and helps prevent unauthorized access, even if user credentials are compromised.

  7. Implement Email Spoofing Protection: Configure email servers and email security gateways to detect and prevent email spoofing attacks, where attackers impersonate legitimate senders to deceive recipients. Implement technologies like Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and Domain-based Message Authentication, Reporting, and Conformance (DMARC) to validate sender identities and prevent email spoofing.

  8. Regularly Update Email Security Policies and Procedures: Review and update email security policies, procedures, and configurations regularly to adapt to evolving threats and industry best practices. Ensure that email security controls are aligned with organizational security objectives and compliance requirements.

  9. Monitor and Analyze Email Security Logs: Implement robust logging and monitoring mechanisms to track email-related activities, detect anomalies, and investigate security incidents promptly. Analyze email security logs for indicators of compromise (IOCs) and anomalous behavior that may indicate a potential security breach.

  10. Collaborate with Email Service Providers: Partner with reputable email service providers and security vendors to leverage their expertise, tools, and threat intelligence for enhancing email security. Stay informed about emerging threats and security trends in the email ecosystem to proactively defend against new attack vectors.

  11. Deploy Advanced Threat Protection (ATP) Solutions: Invest in advanced email security solutions that offer features such as sandboxing, threat intelligence, behavior analysis, and machine learning to detect and mitigate sophisticated email threats like zero-day malware, advanced persistent threats (APTs), and polymorphic malware.

  12. Implement Email Fraud Detection: Utilize email fraud detection solutions that analyze email headers, content, and sender behavior patterns to identify signs of email fraud, business email compromise (BEC), and CEO fraud. These solutions can help detect fraudulent emails impersonating legitimate executives or vendors and prevent financial losses.

  13. Enforce Email Authentication Policies: Enforce strict email authentication policies and configuration settings to prevent unauthorized email spoofing and impersonation attempts. Configure email servers to reject or quarantine emails that fail authentication checks, such as SPF, DKIM, and DMARC validation.

  14. Conduct Phishing Simulation Exercises: Conduct regular phishing simulation exercises to assess users’ susceptibility to phishing attacks and measure the effectiveness of security awareness training. Use simulated phishing emails with realistic scenarios to educate users about phishing risks and reinforce safe email practices.

  15. Enable Email Banner Notifications: Enable email banner notifications or warning messages that alert users when they receive emails from external senders or domains. These banners can help users identify emails originating from outside the organization and exercise caution when interacting with unknown or suspicious messages.

  16. Implement Data Loss Prevention (DLP) Policies: Deploy DLP solutions to monitor and prevent the unauthorized transmission of sensitive or confidential data via email. Configure DLP policies to scan outbound emails for sensitive information such as personally identifiable information (PII), financial data, and intellectual property, and enforce encryption or blocking rules as needed.

  17. Establish Incident Response Procedures: Develop and document incident response procedures specifically for email security incidents, including phishing attacks, malware infections, and unauthorized access attempts. Define roles and responsibilities, escalation paths, and containment measures to minimize the impact of email-related security incidents.

  18. Conduct Regular Security Audits and Penetration Testing: Perform regular security audits and penetration testing of email systems, configurations, and controls to identify vulnerabilities and weaknesses that could be exploited by attackers. Address any identified security gaps promptly and implement remediation measures to strengthen email security posture.

  19. Enable Email Authentication Bypass for Sensitive Emails: Implement email authentication bypass mechanisms for sensitive emails or communications that may be impacted by strict email security policies. Allow authorized users or departments to send emails without being subjected to certain email security checks or restrictions, while still maintaining overall security controls.

  20. Stay Informed About Emerging Threats and Trends: Stay abreast of emerging email security threats, tactics, and trends by monitoring cybersecurity news, threat intelligence reports, and industry alerts. Participate in information sharing forums, security communities, and industry events to exchange insights and best practices with peers and experts.

  21. Implement Email Authentication Whitelists and Blacklists: Maintain whitelists and blacklists of trusted and untrusted email senders, domains, and IP addresses to control inbound email traffic. Use these lists to allow or block emails from known sources based on their reputation and trustworthiness.

  22. Enable Email Link Protection: Implement email link protection mechanisms to automatically scan and rewrite URLs in incoming emails to redirect them through a secure proxy or filtering service. This helps protect users from accessing malicious websites or phishing landing pages by inspecting and blocking suspicious links in real-time.

  23. Deploy Email Quarantine and Remediation: Implement email quarantine solutions that automatically quarantine suspicious or potentially harmful emails for further analysis. Enable administrators to review and release legitimate emails while blocking or deleting malicious ones. Additionally, deploy automated remediation actions to mitigate the impact of email-borne threats.

  24. Monitor User Behavior Analytics (UBA): Utilize user behavior analytics (UBA) to monitor users’ email-related activities and detect anomalous behavior indicative of security incidents or insider threats. Analyze patterns such as unusual email forwarding, large attachments, or access from unfamiliar locations to identify potential security risks.

  25. Integrate Email Security with Endpoint Protection: Integrate email security solutions with endpoint protection platforms (EPP) and endpoint detection and response (EDR) solutions to provide comprehensive security coverage across email and endpoint environments. This integrated approach helps detect and respond to email-borne threats at multiple layers of the security stack.

  26. Enable Email Archiving and Retention: Implement email archiving and retention policies to ensure compliance with regulatory requirements and facilitate e-discovery in legal proceedings. Archive emails securely to preserve their integrity and maintain access to historical email communications for auditing and investigative purposes.

  27. Establish Secure Email Gateways (SEGs): Deploy secure email gateways (SEGs) to act as an intermediary between external email servers and the organization’s email infrastructure. SEGs provide advanced threat protection, data loss prevention (DLP), and encryption capabilities to secure email communications and prevent email-based attacks.

  28. Adopt Zero Trust Email Security Model: Embrace the zero trust email security model, which assumes that all emails, attachments, and links are potentially malicious and should be verified and validated before being accessed or executed. Implement controls such as micro-segmentation, least privilege access, and continuous authentication to enforce zero trust principles for email security.

  29. Regularly Backup Email Data: Implement regular backups of email data to protect against data loss due to email system failures, ransomware attacks, or accidental deletion. Store backups securely in offsite locations or cloud environments with encryption and access controls to ensure data integrity and availability.

  30. Engage in Threat Intelligence Sharing: Participate in threat intelligence sharing initiatives and industry collaborations to exchange information and insights about emerging email threats, tactics, and indicators of compromise (IOCs). Share threat intelligence with trusted partners, vendors, and cybersecurity communities to enhance collective defense against email-based attacks.

By implementing these advanced strategies and best practices, organizations can strengthen their email security posture and better protect network users from a wide range of malicious email threats. Additionally, ongoing monitoring, assessment, and adaptation are essential for maintaining effective email security in the face of evolving cyber threats and attack techniques.

Case Study 1: Mimecast

Challenge: Mimecast, a leading provider of cloud-based email management and security solutions, faced the challenge of protecting organizations from advanced email-borne threats such as phishing, ransomware, and business email compromise (BEC).


Comprehensive Email Security Suite: Mimecast offers a comprehensive suite of email security solutions, including email filtering, threat intelligence, URL protection, attachment sandboxing, and impersonation protection. These solutions help organizations detect, prevent, and respond to a wide range of email-based threats in real-time.

Advanced Threat Detection and Response: Mimecast leverages advanced threat detection techniques such as machine learning, behavioral analysis, and threat intelligence feeds to identify and block malicious emails before they reach users’ inboxes. The company’s threat detection capabilities enable proactive defense against evolving email threats.

User Awareness Training: Mimecast provides user awareness training and education resources to help organizations educate their employees about email security best practices, recognize phishing attempts, and report suspicious emails. By empowering users to identify and respond to email threats effectively, Mimecast helps strengthen the human layer of defense.


Enhanced Email Security: By deploying Mimecast’s email security solutions, organizations improve their overall email security posture and protect against advanced threats such as phishing, malware, and email fraud. Mimecast’s threat detection capabilities help organizations detect and block malicious emails in real-time, reducing the risk of security incidents and data breaches.

Improved User Awareness: Mimecast’s user awareness training programs help organizations raise employee awareness about email security risks and educate them on how to identify and respond to email-based threats. As employees become more vigilant and security-aware, the likelihood of falling victim to phishing attacks and other email scams decreases.


Case Study 2: University of California, Berkeley

Challenge: The University of California, Berkeley, faced the challenge of securing its email infrastructure and protecting faculty, staff, and students from email-based threats such as phishing, malware, and spam.


Email Security Gateway Deployment: The University of California, Berkeley deployed an email security gateway solution to filter inbound and outbound email traffic, detect malicious content, and block spam and phishing emails. The email security gateway helps protect users’ mailboxes from unwanted and potentially harmful emails.

Phishing Simulation and Training: The university conducted phishing simulation exercises to assess the susceptibility of faculty, staff, and students to phishing attacks. Based on the results of the simulations, targeted email security training and awareness campaigns were conducted to educate users about phishing risks and teach them how to recognize and report suspicious emails.

Email Encryption and Data Protection: The University of California, Berkeley implemented email encryption and data protection measures to secure sensitive or confidential information transmitted via email. Encryption technologies help protect email communications from unauthorized access and ensure compliance with privacy regulations.


Reduced Email-Related Risks: By deploying email security gateways, conducting phishing simulation exercises, and implementing email encryption and data protection measures, the University of California, Berkeley improved its email security posture and reduced the risk of email-related security incidents. The university’s proactive approach to email security helps protect faculty, staff, and students from phishing, malware, and data breaches.

Enhanced User Awareness: Through phishing simulation exercises and security awareness training programs, the university increased user awareness about email security risks and educated faculty, staff, and students on how to recognize and respond to phishing attempts. As a result, users became more vigilant and security-conscious when handling email communications.


Case Study 3: NHS Digital (National Health Service Digital)

Challenge: NHS Digital, the national provider of information, data, and IT systems for the National Health Service (NHS) in England, faced significant email security challenges, particularly in protecting sensitive patient data and preventing phishing attacks.


Email Security Gateway Deployment: NHS Digital deployed an email security gateway solution to filter inbound and outbound email traffic for the entire NHS network. The gateway solution employed advanced threat detection mechanisms, including content filtering, URL scanning, and attachment sandboxing, to identify and block malicious emails and attachments.

User Training and Awareness Programs: NHS Digital conducted regular training and awareness programs to educate healthcare professionals and staff about email security best practices, phishing awareness, and data protection guidelines. Training sessions included simulated phishing exercises to assess users’ susceptibility to phishing attacks and reinforce security awareness.

Email Encryption and Data Loss Prevention (DLP): NHS Digital implemented email encryption and DLP measures to protect sensitive patient information transmitted via email. Encryption technologies were used to secure emails containing confidential patient data, while DLP solutions monitored outbound emails for policy violations and prevented data leakage.


Improved Email Security: By deploying an email security gateway and implementing user training and awareness programs, NHS Digital strengthened its email security posture and reduced the risk of email-related security incidents. The gateway solution effectively blocked malicious emails and attachments, while user training initiatives helped raise awareness about phishing threats and promote security-conscious behavior.

Enhanced Data Protection: NHS Digital’s email encryption and DLP measures helped protect sensitive patient data from unauthorized access and data breaches. Encryption technologies ensured the confidentiality of patient information transmitted via email, while DLP solutions prevented accidental or intentional data leakage.


Case Study 4: Bank of America

Challenge: Bank of America, one of the largest financial institutions in the United States, faced significant email security challenges related to phishing, account takeover (ATO) attacks, and financial fraud targeting its customers and employees.


Advanced Threat Detection Solutions: Bank of America deployed advanced email security solutions with robust threat detection capabilities to detect and block phishing emails, malware, and fraudulent messages targeting its customers and employees. The bank utilized machine learning, artificial intelligence (AI), and behavioral analytics to identify and mitigate email-based threats in real-time.

Multi-Factor Authentication (MFA): Bank of America implemented multi-factor authentication (MFA) for employee email accounts and customer-facing applications to enhance account security and prevent unauthorized access. MFA required users to authenticate using multiple factors, such as passwords, security tokens, or biometric verification, before accessing their accounts.

Fraud Prevention and Incident Response: Bank of America established dedicated fraud prevention and incident response teams to monitor email-related threats, investigate security incidents, and mitigate fraudulent activities targeting its customers and employees. The bank implemented proactive measures to detect and prevent account takeover attempts, unauthorized transactions, and email-based scams.


Reduced Fraudulent Activities: By deploying advanced threat detection solutions, implementing multi-factor authentication, and establishing dedicated fraud prevention teams, Bank of America significantly reduced the incidence of email-related fraud targeting its customers and employees. The bank’s proactive approach to email security helped detect and mitigate fraudulent activities in real-time, minimizing the impact on account holders and safeguarding their financial assets.

Enhanced Customer Trust and Confidence: Bank of America’s investment in email security and fraud prevention initiatives bolstered customer trust and confidence in the bank’s ability to protect their accounts and sensitive information. By demonstrating a commitment to security and proactive measures to combat email-based threats, the bank strengthened its reputation as a trusted financial institution.


These case studies demonstrate how organizations in diverse sectors, such as healthcare and finance, have addressed email security challenges and protected their network users from malicious emails through a combination of technology, training, and incident response measures. By implementing robust email security solutions, conducting user training programs, and establishing proactive fraud prevention measures, organizations can mitigate the risk of email-related threats and safeguard their users’ data and assets effectively.