Requirement
Essential Cybersecurity Controls (ECC – 2 : 2024) - Control - 2-4-2 – The cybersecurity requirements for email service must be implemented.
Understanding the Requirement
This control requires an organization to implement defined cybersecurity protections for its email service to reduce risk from spam, phishing, and other email-borne threats. Under the Essential Cybersecurity Controls (ECC – 2 : 2024), practical expectations include deploying approved email-filtering technologies, subscribing to reputable email protection services to detect phishing and spam, and ensuring email access is routed through an intermediary (for example a load balancer or gateway) so traffic can be inspected and controlled. For SMBs this means combining policy, third-party services, and gateway architecture to protect inbound and outbound email.
Technical Implementation
-
Use a dedicated email security gateway or cloud email protection service: Select a managed provider (secure email gateway or cloud-based filtering) that offers advanced threat detection (sandboxing, attachment and URL analysis, reputation and heuristics). Configure MX records to route incoming mail through the provider so all mail is filtered before reaching your mail server or mailboxes.
-
Enforce anti-phishing and spam controls: Enable and tune features such as URL rewriting and click-time link analysis, attachment sandboxing, and machine-learning based phishing detection. Maintain an active subscription or licensing with the vendor so you receive threat intelligence and signature updates promptly.
-
Require intermediary access and centralized inspection: Place email services behind an intermediary — a load balancer or an email gateway — that performs TLS termination, forwards validated traffic to your mail servers, and provides logging and centralized policy enforcement. This intermediary should support high availability for continuity and be part of your network segmentation strategy.
-
Implement email authentication standards: Publish and enforce SPF, DKIM, and DMARC records to reduce spoofing and help receivers classify malicious mail. Monitor DMARC reports and act on them to tighten policies over time (none → quarantine → reject) while avoiding mail flow disruption.
-
Harden access and monitoring: Require multi-factor authentication for email admin accounts and remote access to mailboxes; enforce least privilege. Enable logging and forward email gateway logs to a central SIEM or log collector for alerting and incident investigation. Schedule regular testing of filters (phishing simulations) and review quarantine policies.
Example in a Small or Medium Business
A 75-person professional services firm moved its email to a cloud-hosted mail platform and needed strong protections without a dedicated security team. They subscribed to a managed email security service that provides advanced filtering, URL rewriting, and attachment sandboxing. The firm updated their MX records so every incoming message first reaches the provider's gateway; the gateway enforces TLS, filters spam, blocks phishing attempts, and forwards only validated mail to the cloud mailboxes. The IT manager also configured SPF, DKIM, and a DMARC policy set to quarantine, and reviewed daily DMARC reports to address misconfigurations. For redundancy and control they placed a lightweight load balancer in front of on-premise connectors to enforce the organization's outbound mail policies and to centralize logging. Administrative access to the mail platform and the email protection console requires MFA and is limited to two trained staff members. Over the first three months they tuned filtering rules to reduce false positives, ran a phishing simulation to raise staff awareness, and verified that alerts from the gateway were integrated into their logging/monitoring process so suspected attacks are investigated quickly.
Summary
Implementing this control requires a mix of policy, subscription-based protections, and network design: use approved email protection technologies to analyze and filter messages, maintain active vendor subscriptions for up-to-date threat intelligence, enforce email authentication (SPF/DKIM/DMARC), and route email through an intermediary such as a gateway or load balancer for centralized inspection and logging. Together these measures reduce spam and phishing risk, make email source validation effective, and provide the visibility needed for detection and response appropriate for an SMB.
