Summary
Combating email spoofing involves a multi-faceted approach. Implementing SPF, DKIM, and DMARC with a 'reject' policy is crucial, though DMARC doesn't protect the Reply-To address. Regularly monitor DMARC reports to detect unauthorized senders. Secure website forms and prevent email list scraping. Train employees and educate customers on identifying spoofed emails. Monitor domain reputation using tools like Google Postmaster Tools and consider implementing BIMI. Employ subdomains, a dedicated IP address, and monitor security breaches. Report incidents to authorities and consider DNSSEC and MTA-STS. If DMARC is set correctly, the responsibility falls on receiving domains to honour the policy.
Key findings
- Email Authentication: SPF, DKIM, and DMARC are essential for authenticating email and setting policies.
- DMARC Limitations: DMARC does not protect the Reply-To address.
- Monitoring and Reporting: Regularly monitor DMARC reports and report spoofing incidents to authorities.
- Website Security: Secure website forms and prevent email list scraping.
- Education: Train employees and educate customers on identifying spoofed emails.
- Reputation Monitoring: Monitor domain reputation using tools like Google Postmaster Tools.
- Brand Indicators: Implement BIMI to help recipients identify legitimate emails.
- Network Segmentation: Employ subdomains to isolate the impact of spoofing attacks.
- IP Reputation: Using a dedicated IP address can improve domain reputation.
- Breach Awareness: Monitor security breaches and data dumps.
- DNS Security: Implement DNSSEC for added DNS record security.
- Transport Layer Security: Using MTA-STS enforce TLS encryption for SMTP connections
- Receiving Domain Responsibility: With DMARC setup correctly, receiving domains are responsible for policy enforcement.
Key considerations
- Holistic Approach: A combination of technical measures, education, and monitoring is needed.
- Technical Complexity: Implementing these measures can be technically complex.
- Ongoing Effort: Requires continuous monitoring, maintenance, and adaptation.
- Reply-To Handling: Address the vulnerability of the Reply-To address using alternative methods.
- DMARC Impact: Be aware of the impact of a 'reject' DMARC policy on legitimate emails and monitor accordingly.
What email marketers say
11 marketer opinions
To combat email spoofing, implement strong authentication measures such as SPF, DKIM, and DMARC with a strict 'reject' policy. Regularly monitor DMARC reports to identify unauthorized senders and spoofing attempts. Train employees to recognize spoofed emails and report incidents. Proactively prevent email list scraping on your website using CAPTCHAs and rate limiting. Monitor your domain's reputation using tools like Google Postmaster Tools. Consider implementing BIMI to display your brand logo in supporting inboxes, and use subdomains to isolate the impact of attacks. Using a dedicated IP and monitoring for security breaches are beneficial. Remember that DMARC does not protect the Reply-To address.
Key opinions
- Authentication: SPF, DKIM, and DMARC with p=reject are crucial for email authentication and policy enforcement.
- DMARC Monitoring: Regular DMARC report analysis is essential for identifying unauthorized senders and potential spoofing.
- Employee Training: Educating employees on identifying spoofed emails is vital to prevent phishing attacks.
- Prevention: Preventing email list scraping through CAPTCHAs and rate limiting reduces spoofing risks.
- Reputation: Monitoring domain reputation helps identify malicious use of your domain.
- Brand Indicators: BIMI can help users identify legitimate emails from your domain.
- Subdomains: Using subdomains isolates the impact of spoofing and simplifies security policy implementation.
- Dedicated IP: A dedicated IP address can improve domain reputation and identify spoofing.
- Breach Monitoring: Monitoring for data breaches can identify compromised accounts used for spoofing.
- Reply-To: DMARC does not protect the Reply-To address; other measures might be needed.
Key considerations
- DMARC Policy: Setting a DMARC policy to 'reject' is essential but requires careful monitoring to avoid blocking legitimate emails.
- Comprehensive Approach: A multi-layered approach combining technical measures, employee training, and monitoring is most effective.
- Ongoing Monitoring: Email spoofing is an evolving threat; continuous monitoring and adaptation are crucial.
- Customer Awareness: Informing customers about potential spoofing helps them protect themselves and your brand.
- Resource Allocation: Implementing and maintaining these measures requires dedicated resources and expertise.
Marketer view
Email marketer from MXToolbox shares monitoring your domain's reputation with services like Google Postmaster Tools can help you identify if your domain is being used for malicious purposes and take steps to mitigate the damage.
27 Jul 2023 - MXToolbox
Marketer view
Email marketer from EasyDMARC explains using subdomains for different email purposes (e.g., marketing, transactional) can help isolate the impact of spoofing attacks and make it easier to implement security policies.
29 Apr 2022 - EasyDMARC
What the experts say
4 expert opinions
Experts recommend several steps to combat email spoofing. Firstly, secure your website's forms to prevent spammers from abusing them to send authenticated spam. Secondly, report email spoofing incidents to government agencies like the FTC or IC3. Additionally, advise your customers about the possibility of email spoofing and educate them on how to identify suspicious emails. Finally, implement DMARC to protect your domain from spoofing and phishing attacks.
Key opinions
- Form Security: Securing website forms prevents spammers from using them as a spam vector.
- Reporting Incidents: Reporting spoofing incidents to government agencies helps track and combat these attacks.
- Customer Education: Educating customers on identifying suspicious emails protects them from phishing.
- DMARC Implementation: DMARC is a primary tool for preventing email spoofing and phishing attacks.
Key considerations
- Website Security: Regularly audit and update website security to prevent form abuse.
- Clear Communication: Provide clear and concise information to customers about email spoofing risks.
- DMARC Setup: Properly configure and monitor DMARC to ensure effective protection.
- Legal Action: Understand the legal implications and steps for reporting and addressing spoofing incidents.
Expert view
Expert from Spam Resource explains that you can report email spoofing incidents to government agencies like the FTC (Federal Trade Commission) or the FBI’s Internet Crime Complaint Center (IC3).
6 Jan 2025 - Spam Resource
Expert view
Expert from Spam Resource shares advising your customers about the possibility of email spoofing and how to identify suspicious emails can help protect them from phishing attacks that use your spoofed domain. This can be done through website announcements, social media posts, or email newsletters.
31 May 2025 - Spam Resource
What the documentation says
5 technical articles
Technical documentation highlights several key steps to prevent email spoofing. SPF records authorize sending sources for your domain, DKIM adds a digital signature for message integrity, and DMARC builds on these by defining handling policies for failed authentication. DNSSEC secures DNS records against tampering, while MTA-STS enforces TLS encryption for SMTP connections. Implementing these measures in your DNS settings and email platform configurations is crucial.
Key findings
- SPF Records: SPF records authorize IP addresses and domains to send emails on your behalf.
- DKIM Signatures: DKIM adds a digital signature to ensure message integrity and domain authenticity.
- DMARC Policies: DMARC specifies how receiving servers should handle emails failing authentication.
- DNSSEC Security: DNSSEC secures DNS records to prevent tampering and DNS-based spoofing.
- MTA-STS Encryption: MTA-STS enforces TLS encryption for SMTP connections, enhancing security in transit.
Key considerations
- DNS Configuration: Proper configuration of SPF, DKIM, and DMARC in DNS settings is essential.
- Email Platform Settings: Enable DKIM signing and other security features in your email platform.
- Complexity: Implementing these measures can be technically complex and may require expert assistance.
- Compatibility: Ensure compatibility and proper implementation across different email providers and systems.
- Ongoing Maintenance: Regularly review and update configurations to adapt to evolving threats.
Technical article
Documentation from DMARC.org explains DMARC builds upon SPF and DKIM by allowing you to specify how receiving servers should handle emails that fail authentication checks (e.g., reject, quarantine). Implement a DMARC policy in your domain's DNS settings.
19 Aug 2021 - DMARC.org
Technical article
Documentation from RFC Editor explains MTA-STS (Mail Transfer Agent Strict Transport Security) is a mechanism enabling mail service providers (MSPs) to declare their ability to receive TLS 1.2 or higher encrypted SMTP connections and for sending MTAs to discover and enforce such policies.
2 Nov 2021 - RFC Editor
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