Harden Your Email Stack After Phishing
The threat landscape for phishing attacks continues to evolve. Even seasoned professionals can fall victim, as demonstrated by a recent incident involving a senior Sophos employee. In March 2025, they entered their credentials into a fake login page, resulting in a multi-factor authentication (MFA) bypass. Although the threat actor attempted to infiltrate our network, they ultimately failed. This incident underscores the necessity for robust, layered security controls and a culture that promotes internal cooperation and encourages reporting mistakes without fear.
To fortify your email stack against phishing threats, consider implementing the following strategies:
– Layered Security: Employ multiple security measures. Relying solely on one method, such as MFA, is insufficient. Combine technologies such as Sophos Email Security, anti-virus solutions, and user training.
– Incident Response Plans: Develop and regularly update incident response plans. These should include protocols for reporting phishing attempts and responding to breaches.
– Cultural Shift: Foster an environment where employees feel safe reporting potential security incidents. This encourages vigilance and quick responses to threats.
In our experience, incidents like this highlight the importance of a proactive security posture. Regularly reviewing and updating your security practices is essential to staying ahead of evolving threats.
To improve email security and deliverability, we recommend implementing SPF, DKIM, and DMARC protocols. These standards not only help authenticate your emails but also protect your domain from being spoofed.
– SPF (Sender Policy Framework): This protocol allows you to specify which IP addresses are permitted to send emails on behalf of your domain. Ensure your SPF record is up to date and includes all legitimate sending sources.
– DKIM (DomainKeys Identified Mail): This adds a digital signature to your emails, which recipients can verify. Implementing DKIM helps prevent email tampering and ensures the integrity of your communications.
– DMARC (Domain-based Message Authentication, Reporting & Conformance): DMARC builds on SPF and DKIM by providing a way for you to manage how your domain handles unauthorised use. Set up a DMARC policy to instruct email receivers on how to handle messages that fail SPF or DKIM checks.
When these protocols are correctly configured, they significantly reduce the risk of business email compromise. The implementation of SPF, DKIM, and DMARC should be a priority for any organisation looking to enhance its email security. Regular audits can help ensure compliance with UK regulations, such as those outlined by the Information Commissioner’s Office (ICO) and Cyber Essentials.
In our opinion, these protocols are not merely best practices but essential components of a comprehensive email security strategy.
Secure Mail Gateway Configuration Tips
Configuring a secure mail gateway is crucial to safeguarding your organisation from phishing threats. Here are configuration tips that can enhance your email security while ensuring compliance with UK regulations:
1. Enable Advanced Threat Protection: Sophos Email Security offers advanced threat protection features. Enable these to block known and unknown phishing attacks.
2. Implement Content Filtering: Set up content filters to scan emails for malicious attachments and links. This proactive measure can prevent harmful content from reaching your users.
3. Set Up Quarantine Policies: Establish quarantine policies for suspicious emails. This allows your IT team to review potentially harmful messages before they reach the inbox.
4. User Awareness Training: While not a technical configuration, educating users about phishing tactics is vital. Regular training sessions can help employees recognise and report phishing attempts.
5. Monitor and Review Logs: Regularly review your mail gateway logs for unusual activity. This can help you identify potential phishing attempts early.
A real-world example of effective mail gateway configuration comes from an organisation that implemented Sophos Email Security. After a thorough review of their gateway settings and policies, they reduced phishing incidents by 75% within six months. This demonstrates the tangible benefits of a well-configured email security system.
In our experience, the combination of robust technical measures and user awareness creates a formidable defence against phishing threats.
We can help you enhance your email security posture — contact us.
