Email security encompasses the strategies, technologies, and protocols that safeguard email communication. It stays to identify unauthorized access proactively, phishing attempts, spoofing, malware, spam, and data breaches. Gateway filters, authentication protocols, encryption, measures to spread user awareness, and compliance processes are designed to ensure the confidentiality, integrity, and availability of email data are included in the strategy.
Why is email security important?
Email security is vital because it protects organizations from increasingly sophisticated cyberattacks that can lead to identity theft, financial loss, and damage to their reputation by offering visibility into blind spots.
Take, for instance, a phishing email that appears to come from a trusted source. It can trick employees into revealing login credentials, bypassing defenses and triggering costly data breaches. This happened in a 2024 attack on a major healthcare organization where healthcare services were disrupted and sensitive health information was exposed.
- Utilizing robust email security protocols, such as SPF, DKIM, and DMARC, helps authenticate sender identities and prevent spoofed emails from reaching users.
- Two-factor authentication (2FA) further secures accounts by requiring a second verification step. It reduces the risk of unauthorized access, even if passwords are compromised. Google reported a 99.9% reduction in automated phishing attacks after enabling 2FA.
- By encrypting emails, organizations or users can ensure that sensitive information will remain confidential; this is demonstrated by law firms that have avoided breaches through the use of encrypted communications.
- Regularly updating security software and training employees to recognize phishing attempts and avoid suspicious links also significantly reduces risks.
Cumulatively, all these strategies help organizations comply with regulations such as GDPR, HIPAA, and PCI DSS, thereby avoiding costly fines and operational disruptions.
Main threats to email security
The primary threats to email security have expanded:
Phishing attacks
Fraudulent hacking attempts where attackers use identities of trusted contacts or organizations to trick users into revealing sensitive information (login credentials or financial details).
For example: An employee might receive an email from their bank, prompting them to click on a malicious link or download infected attachments. Ifclicksed, the link can lead to stolen credentials or ransomware infections. Phishing remains one of the most common and effective attack methods, accounting for approximately 83% of reported cybercrime incidents.
Spoofing and impersonation
Attackers forge legitimate email addresses, making it appear that emails come from a trusted source.
This tactic is used to deceive employees into taking unauthorized actions, such as transferring funds or sharing confidential information. For instance, business email compromise (BEC) scams often begin with spoofed emails that mimic a CEO or vendor requesting urgent payments, resulting in millions of dollars lost globally each year.
Malware and spam
Viruses, trojans, or ransomware delivered through email attachments or malicious links hidden in spam messages are becoming common.
These can infect devices, encrypt critical files for ransom, or spread laterally through networks. Spam floods inboxes, reducing productivity and sometimes bypassing filters, causing disruptions and risks.
Account takeover and BEC
In these attacks, hackers gain control over legitimate email accounts, often through stolen credentials or phishing, to send fraudulent emails, siphon funds, or exfiltrate sensitive data. A well-known case involved a multinational company where attackers hijacked an executive's email account to initiate fake wire transfers amounting to several million dollars.
Data leaks and regulatory non-compliance
Unauthorized access or accidental leaks of sensitive data via email can result in severe legal penalties under regulations such as the GDPR, HIPAA, or PCI DSS.
Not adhering to these regulations can result in hefty fines, as well as damage to the organization's reputation. For example, healthcare providers who have been caught emailing unencrypted patient records have faced hefty fines and lost public confidence.
Cyberthreat vectors are evolving rapidly and marked by sophisticated attack methods and new technologies exploited by threat actors. Zero-day vulnerabilities now serve as critical entry points, often leveraged in combination with advanced malware that dynamically adapts to evade traditional detection tools, including those filtering common file types. AI-driven phishing campaigns have become more convincing with ML to personalize attacks, spear-phishing, and deep fake audio-video content that impersonates trusted individuals. Additionally, attackers increasingly employ vendor and supply chain impersonation, exploiting trusted business relationships to introduce malicious code or gain unauthorized access upstream.
Account takeover attacks remain prevalent. Novel vectors such as QR code-based attacks have surfaced, where malicious codes are circulated physically or digitally to redirect victims to phishing sites or trigger malware downloads. These trends underscore the necessity for advanced defenses like Zero-Trust architectures, behavior-based anomaly detection, segmentation, and comprehensive incident response strategies.
Key facets of email security
Identification of threats and risks
Identifying the specific threats your organization faces is the initial step of ensuring email security.
These include practices like phishing attacks, malware-laden emails, account hijacking attempts, and compliance risks related to data privacy regulations. Security teams often use behavioral analysis and AI-driven anomaly detection to spot unusual email patterns that may indicate sophisticated spear-phishing or BEC attacks, which can easily bypass traditional filters by mimicking trusted users or communication styles.
Collecting security information
Regular and automated scans of corporate email domains, mail servers, and network gateways help uncover vulnerabilities and configuration issues that could be exploited by attackers.
Risk assessment tools like the Digital Risk Analyzer (DRA) perform assertion checks such for SPF, DMARC, SMTP TLS, and MTA-STS to verify sender authenticity and ensure encrypted transmission. Continuous monitoring of inbound and outbound traffic via email gateways and anti-spam filters is also critical to detecting suspicious activities early.
Risk scoring and evaluation
Email systems are evaluated and scored based on the health of their configurations—how the authentication protocols are implemented, encryption status, and historical data of attacks or breaches. For example, domains missing DMARC configurations may be more vulnerable to spoofing, thereby receiving higher risk scores. Risk scoring helps prioritize mitigation efforts to focus on the most vulnerable or high-impact areas.
Mitigation and remediation
Once the risks are identified, the next step is enabling and enforcing email authentication protocols like SPF, DKIM, and DMARC to prevent spoofed emails from reaching users.
Deployment of TLS encryption and MTA-STS policies ensures secure mail delivery and reduces interception risks. Advanced gateways, malware scanners, and spam filters stop harmful payloads and block suspicious emails. Additionally, ongoing user education on recognizing phishing attempts, along with enforcement of strong password policies and MFA fortifies defenses against account takeover.
Documentation and reporting
Maintaining detailed documentation of the policies, risk assessment data, incident responses, and remediation plan is essential for compliance and continuous improvement.
Logs of email security events, configuration changes, and alerts help auditing teams verify adherence to all the regional regulations. Detailed, timestamped records facilitate forensic investigations and enhance incident response capabilities, ensuring transparency and accountability.
Email security assessment
A step-by-step email security assessment process:
Define security criteria
Identify the threats relevant to the email communication of your business. This will help to focus on critical vulnerabilities and legal obligations, ensuring thorough coverage of these areas.
Chart an inventory of email systems
Compile a comprehensive list of all email infrastructure components: email servers, domains, SMTP gateways, and associated applications. Catalog critical authentication and encryption protocols in use, like SPF, DKIM, DMARC, TLS, and MFA. This inventory provides the baseline for risk evaluation and gap detection.
Regular security scans
Utilize tools like DRA to continuously scan your email systems for misconfigurations, vulnerabilities, and suspicious activities.
Conduct granular assertion checks ranging from SPF, DMARC, SMTP TLS, and MTA-STS to validate sender authentication and secure encrypted communications.
Evaluate configurations
Thoroughly verify that all authentication protocols (SPF, DKIM, DMARC), encryption mechanisms (TLS, MTA-STS), and gateway filters are correctly set up and active across all mail flows. Examine the effectiveness of anti-spam/spoofing controls and ensure outbound emails conform to security policies to prevent domain abuse.
Patch weaknesses
Address identified gaps by enabling or correcting configurations, updating software and firmware, and removing obsolete protocols. Implement user access restrictions and enforce strong password policies with mandatory MFA.
Email security assessment checklist
Clearly defined security policy and assigned responsibilities
Establish comprehensive email security policies that delineate roles and responsibilities across IT, security, and user groups to ensure accountability and consistent enforcement of security measures.
Comprehensive inventory of email infrastructure
Creating an inventory of all email servers, user accounts, gateways, and related infrastructure helps to stay updated on the requirements related to asset protection.
Implementation of authentication protocols (SPF, DKIM, DMARC)
Deploy these protocols to authenticate senders, prevent email spoofing, and enhance domain reputation.
Enforcement of encryption standards
Email transmissions can be encrypted with specific protocols (TLS, MTA-STS), to ensure data confidentiality.
Multi-factor authentication (MFA)
Mandating MFA for all users adds an essential layer of protection.
Deploy advanced gateways and threat filters
Utilize secure email gateways that are equipped with sophisticated spam, malware, and phishing filters. They help to analyze email content dynamically and attachments and block malicious payloads.
Regular security scans, audits, and creation of incident response plans
Perform frequent system scans and security audits to identify vulnerabilities, monitor compliance, and update defenses. Maintain a detailed incident response plan to address and mitigate email security breaches promptly.
Ongoing awareness and training to ensure security
Regular user education initiatives can help employees to recognize and avoid email threats.
Centralized logging and documentation
Implement centralized logging for all configuration changes, security events, and incident responses.
Indispensable role of email security tools like Digital Risk Analyzer
Site24x7's Digital Risk Analyzer, a third-party risk assessment tool helps to ensure email security by:
1. Running regular scans will be done for your email domains based on the frequencies selected by the user. All findings are aggregated into comprehensive reports, giving you a clear picture of your real-time security status.
2.Ensuring that emails are legitimate and haven't been tampered with. It also runs assertion checks for the industry's most vital email authentication protocols:
- SPF (Sender Policy Framework): Verifies that incoming emails originate from IP addresses authorized by the domain owner.
- DKIM (Domain Keys Identified Mail): Adds a cryptographic signature to emails.
- DMARC: Provides instructions to receiving mail servers on how to handle emails that fail authentication.
- SMTP TLS (Transport Layer Security): Assesses the encryption capabilities of your mail servers.
- MTA-STS (Mail Transfer Agent Strict Transport Security): Enforces TLS encryption for email traffic.
3. Security rating and actionable insights
DRA's primary output is its detailed reports and security rating. The reports generated by DRA is invaluable for demonstrating compliance with various regulatory requirements (e.g., GDPR, HIPAA, PCI DSS) and internal security policies. It shows due diligence in assessing your defenses.
Crucially, DRA provides specific recommendations and insights on how to improve your grades and strengthen your security. It doesn't perform the remediation itself, but it clearly points out what needs to be done, allowing your IT teams to implement the necessary fixes or reconfiguration.
Best practices for comprehensive email security
Adhering to some of the best practices listed below will significantly strengthen your organization's email defenses.
1. Leverage trusted email providers with robust built-in security
The foundation of your email security begins with your chosen provider. Opt for reputable and established Email Service Providers (ESPs); with features such as Advanced Threat Protection (ATP) for zero-day exploit detection and sandboxing, data loss prevention (DLP), secure archiving, and adherence to industry compliance standards (e.g., ISO 27001, GDPR).
2. Enforce essential email authentication protocols (SPF, DKIM, DMARC)
The above mentioned protocols are essential for verifying sender identity and preventing domain spoofing, critical for establishing trust in email communications.
- SPF (Sender Policy Framework): Publish a DNS record listing authorized mail servers permitted to send email on behalf of your domain. This prevents unauthorized senders from impersonating your organization.
- DKIM (Domain Keys Identified Mail): Implement cryptographic signatures for outgoing emails. This allows receiving servers to verify the email's origin and ensures the message hasn't been tampered with in transit.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance): Build upon SPF and DKIM. DMARC enables you to instruct receiving mail servers on handling emails that fail authentication and provides valuable reports on spoofing attempts against your domain.
- Consistently configuring and monitoring these protocols significantly reduces successful phishing and spoofing attacks, protecting both your brand and your recipients.
3. Apply strong encryption standards (TLS, MTA-STS, S/MIME)
Encrypting email traffic safeguards sensitive information from interception, ensuring confidentiality and integrity.
- TLS (Transport Layer Security): Ensure your mail servers are configured to always use the latest, strong TLS versions for encryption of email in transit between servers. This prevents passive eavesdropping.
- MTA-STS (Mail Transfer Agent Strict Transport Security): Implement MTA-STS to enforce TLS encryption for all email traffic to your domain to prevent attackers from downgrading or stripping TLS, ensuring secure communication even if an initial connection attempt is unencrypted.
- S/MIME (Secure/Multipurpose Internet Mail Extensions): For highly sensitive communications, utilize S/MIME for end-to-end encryption and digital signatures on individual emails and this helps to ensure that only the intended recipient can read the message.
4. Mandate strong password policies and MFA
Even the most advanced platforms can be compromised if credentials are stolen or otherwise breached.
- Strong Passwords: Enforce minimum length (e.g., 12+ characters), complexity (mix of character types), and prohibit password reuse. Encourage the use of password managers.
- MFA: Mandate MFA for all email accounts, especially for privileged users. Asking users to have a second verification factor (e.g., a code from a phone app or a hardware token) makes credential theft significantly harder, even if a password is stolen. MFA is one of the most effective controls against unauthorized access.
5. Deploy advanced email gateways and filtering
Email security gateways act as your primary defense layer, scanning all incoming and outgoing emails before they reach user inboxes or leave the organization.
- Email Security Gateways (ESG): Implement cloud-based or on-premise ESGs with features like comprehensive threat scanning, URL reputation checks, attachment sandboxing (executing suspicious files in an isolated environment), content disarm and reconstruction (CDR), and impersonation protection.
- Advanced filtering: Utilize ML, AI, and real-time threat intelligence to detect and block sophisticated spam, malware (including polymorphic and zero-day threats), and advanced phishing attempts (spear phishing, whaling) that bypass basic filters.
6. Conduct regular security awareness and phishing prevention training
Humans are often the most vulnerable link. Empowering your users is paramount.
- Regular training: Provide initial training for new hires and recurring (e.g., quarterly) refresher training for all employees.
- Content focus: Educate users on how to recognize phishing indicators (suspicious senders, urgent tones, generic greetings, grammatical errors, suspicious links/attachments), understand BEC tactics, and safely handle attachments.
7. Monitor for suspicious activities and review configurations post-incident
Vigilance and continuous improvement are non-negotiable for maintaining a strong security posture.
- Proactive monitoring: Regularly review email logs, DMARC reports, and integrate email security data into a SIEM system. Look for patterns indicative of an attack.
- Post-incident analysis: After any security incident or near-miss, conduct a thorough lessons learned analysis.
Through regular assessments, automation, user training, and incident tracking, organizations can avoid costly breaches, maintain compliance, and preserve trust in email communications.