Understanding DMARC and How it Protects Your Email

DMARC - Blog

Domain based Message Authentication Reporting and Conformance (DMARC) is a system that is used for email validation. It is designed to protect your company’s or business’s email domain from being used to perform email phishing scams, spoofing, or other cyber crimes.

For DMARC to work, it will leverage the authentication techniques for the existing email. The authentication techniques include Domain Keys Identified Mail (DKIM) and Sender Policy Framework (SPF).

Reporting is such an important function in email protection and DMARC ensures it is present. When an individual or a company that owns a domain publishes a DMARC record in their DNS, they can gain insights about who is sending any emails on behalf of the domain. The domain owner can also gain control of the emails that may have been sent on their behalf.

DMARC is useful in protecting domains against spoofing and phishing attacks. When you secure your company’s or individual emails with DMARC, your recipients won’t have a hard time trying to verify if the emails are legit. DMARC confirms with certainty that an email has indeed originated from you. This will prevent other malicious individuals from sending emails using your domain.

How DMARC Email Security Works

DMARC will enable your company to publish your desirable policies to your DNS record while defining different practices to be used for email authentication. It also provides clear instructions to the mail servers on how to enforce these configurations and instructions.

Technically, DMARC helps mail servers analyse if a sent message aligns with the information about the sender and if not, how the email will be handled.

DMARC enables the mail servers to check the alignment of the ‘header from’ in the domain name and the ‘envelope from’ domain name which is used in the SPF authentication method. The alignment between ‘header from’ domain with ‘d=domain name’ is used for the DKIM signature authentication.

When a message fails both DKIM and SPF alignment and authentication tests, the mail servers which will receive it can check the sender’s DMARC email security policy to decide whether to block, accept or even quarantine the email.

DMARC is useful since it also updates the sender domain owner of the decision it makes. This provides a clear insight into the messages which have been sent from the affected domain.

Using DMARC for Email Security to Prevent Spoofing

Cyber criminals often use a legitimate domain to send fraudulent emails to unsuspecting users. This may convince the users to divulge their sensitive and personal data or even wire money to the fraudulent accounts.

DMARC can be used to avoid such attacks by allowing the senders to alert their recipients that their messages will be protected by DKIM and SPF, and the procedure to take if the emails don’t pass either of the authentication protocols set.

DMARC reduces the risk of the recipients receiving fraudulent emails or even getting exposed to them through proper email security policies that handles failed messages. This also helps in protecting a sender’s domain address from being used for fraudulent purposes.

Cyber criminals are always evolving their attack mechanisms. DMARC may be effective in stopping some types of attacks but it may not even detect others that have found new vulnerabilities in a company’s system.

DMARC email security can be used together with other solutions for advanced security against all types of cyber attacks. This ensures a multi-layered approach and a highly effective security strategy.

Advantages of DMARC Email Security

The benefits of using DMARC to boost your email security are;

  1. Ease of troubleshooting delivery issues. When you use DMARC to filter your company’s emails, it will be easier to get valuable insights about problems experienced with email authentication through DKIM and SPF.
  2. It offers greater visibility. Which is achieved by reporting the outbound emails sent from a company’s domain. DMARC email security framework will provide a clear insight into all the messages sent using the company’s domain or other third parties who have been used to send emails through the company’s domain.
  3. Prevents certain spoofing and phishing attacks. When properly implemented, DMARC can protect your business against certain types of cyber attacks. You can use DMARC with other email security solutions to capture all types of email threats.

The Three DMARC Policies in Detail

DMARC has three possible policies;

Monitor Policy

This is the none policy. This DMARC policy instructs the email receivers to send the DMARC records and reports to the addresses that have been published in the RUF or RUA tag of the DMARC records.

This is a monitoring-only policy since it is the recommended starting policy to gain insights into your email messaging channel. Although the none policy will give information about the email channel, it will not instruct the receivers of the email to handle the emails that have failed the DMARC SPF and DKIM checks separately.

This policy will only provides information about who is sending an email on behalf of a certain domain and it will not affect email message deliverability.

Quarantine Policy

This is the second DMARC policy. It is responsible for sending DMARC reports and instructing the emails servers to put all those emails that fail the DMARC checks in the spam folder of the recipient.

When emails pass the DMARC checks, they will be delivered into the primary inbox of the recipient. Through such steps, the quarantine policy will successfully mitigate the impact caused by any spoofing attack. However, the spoofed emails will be delivered into the spam folder of the receiver.

Reject Policy

This is the third DMARC policy. Apart from sending the DMARC reports, this policy also instructs the email receivers not to deliver emails that fail to meet the DMARC checks. The emails that will pass the DMARC checks are delivered to the primary inbox of the receiver.

This policy also reduces the impact of spoofing. The DMARC reject policy will also ensure all the incorrect emails, which are the spoofing emails are deleted by the receiver of the email and don’t land in their inbox.

Implementing DMARC is a great way to ensure domain-based message authentication of all email messages. After filtering all the messages and ensuring the DNS records signs match with those of the sender, email messages sent are assured to be legitimate messages coming from genuine IP addresses.

DMARC will also give aggregate reports of all the emails blocked since they were suspected to be spoofing emails and the domain of the company they came from.

Although DMARC will not prevent all types of email attacks, it is always reliable for identifying most spoofing and phishing attacks. You should consider to complement other email security tools together with DMARC for better protection.

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