Risks of False DMARC Reports: What Your Provider Must Do

Introduction

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an essential protocol for protecting your domain against email-based fraud and abuse. However, the effectiveness of DMARC hinges significantly on the accuracy and integrity of the reports you use to make informed security decisions.

Erroneous DMARC reports can at best mislead organisations, wasting valuable resources, or lead to misconfigured email services and potentially severe security lapses.

In this post, we'll explore the risks associated with inaccurate or false DMARC reports, essential checks your DMARC provider should perform, and how VerifyDMARC addresses these challenges.

The Dangers of Inaccurate DMARC Reports

Inaccurate DMARC reports pose significant risks. They can provide a false sense of security or, conversely, trigger unwarranted alarms that waste your organisation's resources on non-issues. Erroneous data might lead you to allow list malicious domains or block legitimate senders, affecting your communication and business operations. Therefore, ensuring the authenticity and accuracy of DMARC reports is crucial for effective email security management.

Essential Checks by Your DMARC Reporting Provider

A reliable DMARC report provider must implement rigorous checks to maintain data integrity:

1. DMARC Compliance Enforcement: Your provider should enforce DMARC compliance on incoming reports to confirm that they genuinely originate from the stated sender, adhering to established email authentication standards.
2. Sender Verification: It's crucial that your provider verifies the sender against an allow list of established and reputable organisations. This step ensures that the sender has credible standing.
3. Data Validation: Each report should be validated against the DMARC XML schema to ensure the structure and content meet industry standards. This validation prevents the processing of malformed or incomplete data.

VerifyDMARC’s Approach

At VerifyDMARC, we recognise the critical nature of DMARC report accuracy. We implement multiple layers of checks to ensure the data you use is reliable:

• We enforce DMARC compliance on all incoming reports, verifying that they truly come from their claimed source.
• We verify the report sender against an allow list of reputable mail receivers we trust to be credible.
• We validate the report data against the DMARC XML schema, ensuring it is structurally correct and is of adequate quality to ingest.

Thanks to these measures, we confidently process 99% of incoming DMARC reports, providing our clients with data they can trust when making informed security decisions.

Considerations and Limitations

While our measures are robust, they do come with certain operational considerations. For instance, DMARC reports cannot be manually forwarded to us unless they pass validation checks and preserve DKIM signatures during forwarding. This limitation is essential to prevent ingestion of potentially tampered or spoofed reports, maintaining the integrity of the data we present on our Dashboard.

Conclusion

Choosing the right DMARC report provider is crucial for maintaining the security and integrity of your email communications. Providers like VerifyDMARC go to great lengths to ensure that the data you receive is not only accurate but also actionable. By understanding what to look for in a provider and the potential drawbacks of certain security measures, you can better navigate the complexities of email security and DMARC implementation.

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