Domain-based Message Authentication, Reporting, and Conformance (DMARC) plays a vital role in maintaining email security. It's crucial for IT experts to grasp the interpretation of DMARC reports to protect their organization's domain from threats like email spoofing and phishing. This guide offers a comprehensive, step-by-step method for effectively analyzing DMARC reports.
Step-by-Step Guide to Interpreting DMARC Reports
1. Understand the Types of DMARC Reports
Aggregate Reports
Aggregate reports, also known as RUA reports, are XML documents that provide comprehensive details about email authentication outcomes. These reports generally feature information such as the IP addresses of sending sources, results from SPF and DKIM validations, and the total count of emails dispatched.
Forensic Reports
Forensic reports, also known as RUF reports, offer a comprehensive analysis and are issued when an email does not pass DMARC authentication. These reports include an example of the unsuccessful email along with explanations for its failure, giving a detailed insight into possible security risks.
2. Identify Key Components of the Report
Source IP Address
Every DMARC report includes the IP addresses of servers that are dispatching emails for your domain. IT specialists need to check that these IPs match those of approved email servers. Any unfamiliar IP addresses could signal unauthorized actions, like attempts at spoofing.
SPF and DKIM Authentication Results
SPF and DKIM serve as the primary methods for verifying email authenticity. The DMARC report will indicate whether each email has successfully passed or failed these authentication checks. Frequent failures could suggest problems with your configuration or that unauthorized entities are trying to send emails using your domain.
- SPF Results: This part shows if the IP address of the sending server aligns with the SPF records of the domain.
- DKIM Results: This part indicates if the digital signature of the email, created by DKIM, corresponds with the public key that you have published in your DNS records.
Disposition
Disposition refers to the action taken on an email that fails DMARC authentication. Possible dispositions include:
- None: No steps were taken; the email was sent as it typically is.
- Quarantine: The email was flagged as potentially harmful and moved to the spam folder of the recipient.
- Reject: The email was completely refused and did not reach the intended recipient.
3. Analyze the Report Data
Look for Consistent Failures
Repeated DMARC failures could suggest that there is an issue with your SPF or DKIM configurations, particularly if genuine emails are being marked as problematic. Conversely, if the failures are originating from unapproved sources, it may point to active spoofing attempts that require your attention.
Pay Attention to High-Volume Sources
If there is a significant amount of email activity originating from a specific IP address or domain, it may be necessary to conduct additional inquiries. For legitimate sources, such as marketing services, make sure they are correctly verified. Conversely, if the sources are not valid, you might have to restrict or manage them to safeguard your domain from unauthorized access.
Evaluate Forensic Reports
Forensic reports offer comprehensive analysis of particular email failures. They can identify weaknesses and aid in refining your DMARC policy. Nevertheless, the extensive detail in these reports can be daunting, so it's important to utilize them thoughtfully.
4. Refine Your DMARC Policy
Start with a “None” Policy
When you initially set up DMARC, begin with a policy set to none. This approach lets you gather data without affecting the delivery of your emails. The objective during this stage is to accumulate sufficient information to verify that your SPF and DKIM settings are accurate.
Move to “Quarantine”
After ensuring that your email authentication is properly configured, think about implementing a quarantine policy. This approach allows you to evaluate your setup by sending potentially harmful emails to the spam folder instead of rejecting them completely.
Implement a “Reject” Policy
Ultimately, after confirming that all valid emails are properly authenticated, implement a rejection policy.
5. Regularly Monitor and Adjust
DMARC should not be treated as a one-time setup. It is crucial to consistently monitor DMARC reports to maintain effective defense against changing threats. Make it a practice to frequently analyze the reports, modify your policies as necessary, and remain alert to any emerging sources of unauthorized emails. Read our guide.