What is a DMARC policy?
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication method that protects against fraudulent emails. DMARC is an essential first line of defense against phishing emails and similar cyberattacks.
DMARC builds on the SPF and DKIM authentication protocols that are currently widely used. By establishing a DMARC policy, organizations can let the email servers know how to validate messages from their domain and what to do with email that fails to authenticate.
While DMARC can provide a critical layer of protection against email spoofing attacks, implementing the DMARC protocol and establishing DMARC policy can be costly and complex, and managing and analyzing DMARC reports on an ongoing basis can be time-consuming. It's no wonder, then, that so many organizations adopting DMARC policy turn to Mimecast for help in implementing and managing the DMARC protocol.
| Microsoft (as of July 2024) and Google (starting February 2024) have announced they will honor DMARC records for consumer and enterprise businesses, indicating a significant shift towards increasing trust in email.
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What does a DMARC policy do?
A DMARC policy helps email receiver systems distinguish legitimate and fraudulent emails. If an email message doesn’t come from an approved domain, the DMARC alerts the receiver systems and tells them how to respond, isolating any potential threats.
What are the various DMARC policy options?
There are three essential DMARC policy options: “none,” “quarantine,” and “reject”
- The “none” policy, also known as “monitor” tells the provider to take no action.
- The “quarantine” policy sends any unauthorized emails into a separate folder, similar to a spam folder.
- The “reject” policy tells the provider to block any unauthorized emails so that they cannot reach recipients.
Why do you need a DMARC policy?
It’s important to have an active DMARC policy to help protect against phishing attacks and ransomware.
A DMARC policy reduces human error when protecting against cyber threats and enables your organization to respond faster and more efficiently to phishing attacks.
Even if your employees are well-trained to recognize and respond to suspicious emails, a DMARC policy will help save them time and trouble by automatically taking protective action against potential threats.
Which DMARC policy should you implement?
The DMARC policy you should implement largely depends on the nature of information your organization needs to protect. To begin with, it is generally advisable to start with a “none” policy for the purpose of legitimizing trusted hosts and domains. This can also help create a sense of any potential threats and monitor suspicious activity without inhibiting any usual legitimate communication.
Once the groundwork has been laid out, the next step is to implement a quarantine policy so that legitimate communication can continue as per usual, but there is now an additional layer of security to filter out potential threats.
Finally, those who have greater needs for security will move towards implementing a reject policy. This is usually the case for financial institutions and healthcare organizations, whereas those who have less sensitive data to protect may continue with a quarantine policy.
Defend against domain spoofing with a DMARC policy
As the number of impersonation and spoofing attacks continues to rise, many organizations are turning to DMARC policy and protocols to stop these malware-less attacks.
In a spoofing attack, a cybercriminal sends an email message that appears to come from someone in your company in an attempt to trick the recipient into transferring money, revealing credentials, or sharing sensitive information. Spoofed emails may target your own employees and customers as well as suppliers and partners.
