What Is a Secure Email Server?

An email server is responsible for sending and receiving emails for an organization. This is a crucial role for corporate cybersecurity due to the sensitivity of the information contained within email traffic, the phishing threat, and the use of email to manage access to other online accounts.

Like other software, email servers have a variety of optional configuration options that impact the security of these systems. A secure email server is one that implements email security best practices to reduce the risk of account takeover, phishing, and other email-related threats.

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Why a Secure Email Server is Important

Email is one of the most common attack vectors used by cybercriminals. Phishing emails can be used to deliver malware, steal credentials, or exfiltrate sensitive data. An attacker with access to email accounts can steal sensitive data from them and potentially expand their access to other accounts controlled via those emails.

A secure email server can help to protect an organization’s email against potential threats. This includes both turning on email security features and deploying email security solutions to identify and block inbound threats. By locking down its email server, an organization dramatically reduces its exposure to cyber threats.

Ways to Secure Your Email Service

Email servers have a variety of features that can be configured to better protect them against cyber threats. Some best practices that can help to secure your organization’s email service include the following:

Configure DKIM: The DomainKeys Identifier Mail (DKIM) protocol uses digital signatures to ensure the integrity of inbound mail. Configuring DKIM prevents an attacker from modifying email to include malicious content.
Set Up SPF: The Sender Policy Framework (SPF) defines the set of IP addresses that can send mail on behalf of a specific domain. Configuring SPF makes it harder for an attacker to send spam or phishing emails while masquerading as your organization.
Implement DMARC: Domain-Based Message Authentication Reporting, and Conformance (DMARC) combines DKIM and SPF. This combination ensures that a message both originated from the alleged sender and has not been modified in transit.
Use a Blocklist: A blocklist is a set of domains or IP addresses that are known to send phishing, spam, or other unwanted emails. Using an IP or DNS blocklist (DNSBL) causes an email server to automatically drop messages from blocked domains.
Configure Mail Relay: An open mail relay can be abused by an attacker to relay spam and other types of malicious and unwanted email. Mail relay should be configured to limit the addresses and domains to which email can be sent.
Control User Access: SMTP servers can be configured to be accessible without authentication, which can enable abuse and use as an open relay. SMTP servers should be configured to require users to authenticate to use its services.
Encrypt Email: Many network protocols, such as the POP3 and IMAP email protocols, are plaintext protocols, making it possible for an attacker to view or modify email traffic in transit. SSL/TLS encryption should be enabled on email servers to provide confidentiality, integrity, and authentication protections.
Implement Strong Authentication: An email server secured with a weak password is potentially vulnerable to a credential guessing attack. Email servers should be secured with a strong password that is changed regularly and reinforced by multi-factor authentication (MFA)

These best practices can help secure a corporate email server against unauthorized access and helps to protect against various attacks. However, implementing strong email server security is not enough to protect against many common types of email attacks, such as phishing.

Secure Email with Check Point

A secure email server protects against an attacker abusing the power of a corporate email server. Corporate email traffic commonly contains sensitive information and may control access to other online accounts. As a result, securing corporate email servers is vitally important to an organization’s cybersecurity. Implementing email server security best practices is an important first step toward protecting these systems against attack and securing email traffic en route to its destination. However, companies also need to protect themselves against malicious content that may be contained within emails. DMARC provides no protection against malicious attachments sent from a legitimate, compromised email account from a trusted third party.

Protecting against email-borne threats requires advanced threat prevention capabilities. This includes the ability to identify phishing emails, detect novel and zero-day malware delivered via email, and remove malicious content from infected documents using Content Disarm and Reconstruction (CDR).

Check Point Harmony Email & Collaboration provides comprehensive protection against phishing attacks delivered over email or via other collaboration platforms, such as Slack, Microsoft Teams, or Sharepoint. To learn more about Check Point Harmony Email & Collaboration and how it can help to protect your organization against email-based threats, feel free to sign up for a free demo today.