Secure Email Gateway (SEG)

A secure email gateway (SEG) is a cybersecurity solution that defends an organization’s email system from threats like spam, phishing, malware, and other email attacks. It is a layer of security between the email infrastructure and the incoming and outgoing email traffic.

These email security gateways are crucial in keeping pace with the growing sophistication and frequency of email-based attacks. They act as a first line of defense, filtering out malicious emails before they reach inboxes. And, given that more than 90% of successful cyberattacks originate with an email, the need for these advanced security solutions is critical.

Email gateways employ innovative technologies like multiple scanning engines and threat intelligence to protect against widespread email-based threats like business email compromise (BEC) attacks. They analyze email traffic at scale, leveraging the cloud’s elasticity to intercept threats at the earliest stages.

Given that billions of domain spoofing emails are sent daily and that the average cost of an organization’s most expensive email attack was over $1 million in 2022, robust email security measures are a must. They’re essential to safeguarding sensitive data and maintaining operational integrity.

• Secure email gateways (SEGs) use features like spam filtering, malware detection, and encryption to protect an organization’s email communications and infrastructure from potential email-based attacks.
• SEGs offer more robust protection than traditional email security protocols. Plus, their on-premises, cloud-based, or hybrid configurations offer organizations flexibility in their chosen solution.
• Email gateways provide state-of-the-art threat detection, plugging into dynamic threat intelligence feeds that continuously update.
• Businesses implementing SEGs can expect enhanced threat detection and response, improved regulatory compliance, lower IT costs, and better customer data protection.

A secure email gateway is a critical line of defense against email-based threats, operating at the network perimeter to inspect incoming and outgoing messages. Here's how it works:

Spam filtering

SEGs employ multiple techniques to identify and block spam:

• Content analysis: Examines email text for suspicious patterns, keywords, and phrases commonly associated with spam.
• Sender reputation: Checks the sender's IP address and domain against databases of known spammers.
• Heuristic analysis: Uses algorithms to detect new spam patterns based on characteristics of known spam.
• Bayesian filtering: Learns from user feedback to improve spam detection over time.

Malware detection

To protect against malicious attachments and links, SEGs use:

• Signature-based scanning: Compares files against databases of known malware signatures.
• Sandboxing: Executes suspicious files in an isolated environment to observe behavior.
• URL filtering: Checks embedded links against lists of known malicious websites.
• Machine learning: Analyzes file characteristics to identify potential threats, even those previously unknown.

Encryption

SEGs often incorporate encryption features to protect sensitive information. This includes:

• TLS encryption: Secures communication between email servers during message transmission.
• Policy-based encryption: Automatically encrypts emails based on content, recipient, or other predefined rules.
• Key management: Handles the creation, distribution, and storage of encryption keys.

How it all works together

Here's how all these components work together to protect your inbox:

1. The gateway scans the message header and content for spam indicators.
2. Attachments are analyzed for malware using multiple detection methods.
3. URLs in the message body are checked against reputation databases.
4. If the email passes these checks, it's encrypted (if necessary) and delivered to the recipient's inbox.
5. Suspicious messages are quarantined or blocked, depending on the configured policies.

SEGs continuously update their threat intelligence and adapt to new attack techniques, providing a robust defense against evolving email-based threats like spam, malware, and data breaches.

The three primary deployment models for secure email gateways are:

• On-premises SEGs: These are installed and operated within an organization's infrastructure. They offer full control over hardware and data, making them suitable for companies with strict compliance requirements. However, they require significant IT resources for maintenance and updates.
• Cloud-based SEGs: Hosted by third-party providers, these offer scalability, automatic updates, and reduced infrastructure costs. They're ideal for organizations with limited IT resources or those prioritizing flexibility. However, they may raise data sovereignty concerns for some industries.
• Hybrid SEGs: Combining on-premises and cloud solutions, hybrid SEGs offer a balance of control and flexibility. They allow organizations to keep sensitive data on-site while leveraging cloud capabilities for scalability and advanced threat protection.

All types provide core features like spam filtering, malware detection, and data loss prevention. The right choice for your organization depends on your IT capabilities, compliance requirements, and scalability needs. Cloud-based solutions are gaining popularity due to their ease of management and continuous updates against evolving threats.

Malware and viruses pose significant risks to security and operational continuity of an organization. Secure email gateways stop these threats before they get to the inbox. SEGs also secure outgoing mail so that threat actors cannot use your company to attack another.

There are several sophisticated mechanisms designed to detect, block, and manage malicious content in emails before they reach the user’s inbox or leave the organization.

Signature-based detection: This method uses a database of known malware and virus signatures to identify threats. The system immediately flags and blocks or quarantines an email or attachment when it matches a known signature.

Heuristic analysis: This involves examining the behavior of an email or attachment to predict whether it might be malicious. This includes analyzing the structure of the code and detecting suspicious patterns that could indicate malware, even if the specific threat has not been previously identified.

Sandboxing: This security technique opens attachments or links in a virtual, isolated environment. This environment, or “sandbox,” allows the secure email gateway to observe the file's behavior before passing it on to the recipient's inbox. The SEG will block or quarantine files determined to be a threat.

Advanced and zero-day threat protection: By combining signature-based detection, heuristic analysis, and sandboxing, secure email gateways can detect and defend against zero-day attacks and other emerging threats. These features allow the system to respond to new threats quickly, without waiting for updates to signature databases.

Traffic analysis and filtering: The gateway continuously monitors and analyzes email traffic to detect anomalies that may indicate the presence of malware. An unusually high volume of outgoing emails might suggest a compromised account sending spam or malware.

Regular updates and threat intelligence integration: Secure email gateways are regularly updated with the latest threat intelligence and malware definitions. This ensures they remain effective against evolving threats. Many gateways integrate with global threat intelligence networks, allowing them to learn from and adapt to threats detected across many systems worldwide.

URL protection: Threat actors often use malicious links in the body of an email to distribute malware and viruses. Secure email gateways conduct real-time scanning of URLs to check their reputation and content before allowing users to access them.

Dynamic threat intelligence feeds: Secure email gateways use dynamic threat intelligence feeds that provide up-to-date information about malware campaigns, phishing tactics, and virus outbreaks. These feeds help the SEG adjust its filters and detection mechanisms dynamically to catch the latest threats.

SEGs protect against various common threats. They leverage innovative technologies to protect an organization’s digital infrastructure from the following attack vectors:

• Viruses: Secure email gateways employ multiple scanning engines to detect and block email-borne viruses. They use signature-based detection to identify known viruses, heuristic analysis to spot suspicious code patterns, and behavioral analysis to identify virus-like activities.
• Malware: To combat malware, SEGs use advanced threat protection (ATP) with sandboxing to safely analyze suspicious attachments. They perform real-time scanning of attachments and embedded links while employing machine learning algorithms to detect new malware variants. These techniques help prevent malicious software from infiltrating the organization's network through email.
• Phishing attacks: SEGs protect against phishing by analyzing email content for suspicious patterns and keywords. They check sender reputation and authenticity using protocols like Domain Message Authentication Reporting and Conformance (DMARC), filter URLs to block access to known phishing websites, and leverage AI and natural language processing (NLP) to detect sophisticated social engineering attempts.
• Ransomware: SEGs help protect against ransomware by blocking malicious attachments that may contain ransomware payloads. They scan and sandbox suspicious links that could lead to ransomware downloads and employ advanced threat intelligence to identify emerging ransomware campaigns.

Here is a side-by-side look at how each technology component of secure email gateways guards against these threats.

Secure email gateways significantly contribute to various aspects of business success. They provide a foundational layer of security that not only protects but also enhances various business operations, ensuring regulatory compliance, fostering trust, and ultimately supporting long-term business growth and sustainability.

• Enhanced security and threat protection reduces the risk of security incidents, helps maintain the integrity of business operations, and protects against financial losses and reputational damage.
  
• Compliance and regulatory adherence features help avoid legal penalties, costly lawsuits, and damage to reputation by ensuring that the organization meets regulatory standards.
  
• Lower IT maintenance costs and prevention of costly security incidents lead directly to enterprise-wide financial savings and more resources for business initiatives.
  
• Protecting customer data enhances trust and supports a strong corporate image, directly impacting business growth and success.
  

Barracuda provides secure email gateway products to help you defend against all email threat types while maintaining a secure communication environment and superior email detection efficacy. These products are available as a standalone solution or as part of our comprehensive cybersecurity platform, which secures data across all threat vectors.

Barracuda offers best-value, feature-rich, one-stop email security solutions that protect against a wide range of threat vectors — all backed by complete, award-winning customer service. Because you are working with one vendor, you benefit from reduced complexity, increased effectiveness and lower total cost of ownership.

Hundreds of thousands of customers worldwide count on Barracuda to protect their email, networks, applications and data. Schedule your Email Protection demo today and discover why so many are making the switch.