Email remains the primary attack vector for cybercriminals, with phishing alone accounting for over 80% of reported security incidents. As threats become more sophisticated, understanding the different types of email security is crucial to maintaining compliance and protecting your organization’s reputation.
What is email security?
Email security includes the technologies and practices designed to protect email and communications from unauthorized access, cyberattacks, and data loss.
47% of IT leaders consider inbound threats their primary concern – and with good reason. A single successful phishing or ransomware attack can lead to devastating consequences, including data theft, financial loss, and reputational damage.
5 types of email security services
1. Secure email gateways (SEGs)
Secure email gateways are the first line of defense against inbound threats. They block malicious emails, filter spam, scan attachments for malware, and quarantine suspicious messages before they reach your inbox.
While SEGs provide essential protection, they operate using predefined rules that struggle to adapt to new threats, and can't detect sophisticated social engineering attacks.
2. API-based protection
API-based security integrates with email platforms like Microsoft 365 and Google Workspace, providing enhanced protection without routing traffic through additional infrastructure. They scan emails pre- and post-delivery, in real time, detect account compromise patterns, and identify sophisticated phishing and business email compromise attempts.
3. Authentication systems
These systems verify that messages have come from legitimate sources. Authentication helps reduce the chances of successful phishing attacks and business email compromise (BEC).
Sender policy framework (SPF)
Specify exactly which mail servers are permitted to send an email on behalf of your domain. This helps prevent email spoofing by verifying the sender’s identity.
DomainKeys Identified Mail (DKIM)
A digital signature to outgoing emails that’s validated by receiving servers. Validation typically occurs at the server level so signatures aren’t generally visible to end-users.
Domain-based message authentication, reporting & conformance (DMARC)
DMARC combines SPF and DKIM to create a comprehensive domain protection solution. It allows domain owners to specify how unauthenticated emails should be handled and provides reporting on email authentication results.
4. Encryption technologies
Encryption protects email content from unauthorized access and ensures that sensitive information remains confidential even if intercepted.
Popular encryption protocols include:
Transport layer security (TLS) and secure sockets layer (SSL)
TLS and SSL are sometimes referred to as digital certificates and secure the connection between email servers during transmission.
Both the sender and recipient need to support the same TLS version for it to be successful. If not, the email will default to unencrypted transmission.
End-to-end encryption (E2EE)
Data is encrypted at every stage of its journey, from one device to another. E2EE ensures only intended recipients can access email content and protects against man-in-the-middle attacks.
Zero-knowledge encryption
Zero-knowledge encryption ensures only the sender and intended recipient(s) have decryption keys. This eliminates vulnerabilities associated with vendor-held keys and provides maximum protection for sensitive communications.
5. Attachment sandboxing
Sandboxing isolates and analyzes email attachments in a secure virtual environment before delivery to users. This approach catches sophisticated threats by running the file and watching what it does, not just what it claims to be.
Common inbound email threats
Here are the major inbound threats organizations face:
Phishing attacks
Phishing is the most common email-based attack. It uses social engineering to trick recipients into revealing credentials or sensitive information. These attacks range from mass campaigns to highly targeted spear phishing aimed at specific individuals. They’ve grown increasingly sophisticated, often leveraging AI to create convincing messages.
Business email compromise (BEC)
BEC attacks involve impersonating executives or trusted partners to trick employees into taking harmful actions, such as unauthorized wire transfers or sharing sensitive information. The average BEC attack costs organizations hundreds of thousands of dollars, with losses often unrecoverable.
Malware and ransomware
Email remains the primary delivery method for malicious software, whether through attachments, links, or drive-by downloads. Once installed, malware can steal information, provide backdoor access, or encrypt critical business data. The cost of ransomware attacks extends beyond ransom payments to include downtime, recovery expenses, and reputational damage.
Spam
While spam’s mostly a nuisance, it can be used as a delivery mechanism for more serious threats. Modern spam often includes malicious elements like tracking pixels that confirm active email addresses for further targeting.
Email security best practices
Protecting against these sophisticated threats requires a multi-layered approach:
Deploy comprehensive security technologies
Implement multiple security layers for the best defense. Use AI-powered solutions for better threat detection and regularly update security tools to address emerging threats.
Adopt zero-trust security principles
Verify every user and access attempt, applying the principle of least privilege. Implement multi-factor authentication for all email accounts.
Invest in effective employee training
Conduct regular phishing simulations and provide just-in-time security guidance. Focus on practical, scenario-based training and create a culture that encourages reporting suspicious activity without fear of blame.
Establish incident response procedures
Document response protocols for different threat types and create clear escalation paths for security incidents. Learn from security events to improve defenses and conduct regular response drills to ensure readiness.
Safeguard your email communications
Sophisticated email threats require sophisticated email security. Multiple layers of protection – intelligent threat detection, smart data loss prevention domain authentication, and zero-knowledge encryption – provide complete email security, with 360-degree protection.
