DMARC - Domain-based Message Authentication Reporting & Conformance
Domain-based Message Authentication, Reporting, and Conformance or DEMARC is an automated email authentication and reporting protocol designed to increase email security by ensuring the authenticity of the sender’s identity.
DEMARC protects a domain from being used by bad actors in an email attack such as spoofing, phishing, and spamming. The protocol helps make certain that the listed sender is a trusted source and who they are supposed to be, making email users more secure and protecting brands against abuse of their images.
DEMARC builds on the commonly deployed and industry-recognized Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) email authentication techniques. DEMARC adds linkage to the author’s domain name with the :From: header and standardized policies for recipient handling of authentication failures. Receivers-to-sender reporting is improved to protect against fraudulent emails. DEMARC enhances mail authentication practices for senders and enables receivers to reject unauthenticated messages.
How DEMARC works?
DEMARC provides the user with instructions on how to handle emails if there are fraudulent. When a DEMARC record check detects a misalignment between an email sender and the address as it appears to the recipient of the email, DEMARC activates an administered protocol that tells the receiving server to either accept the message, quarantine it, or reject it based on policy the sender defines.
The validation process includes DEMARC giving the sender reports on who is attempting to use their domain to send messages. This visibility allows the sender to fine-tune their policy as new cyber threats emerge.
Why DEMARC?
Prior to the creation of DEMARC, the most common standards to defend networks against email attacks were SPF and DKIM. Both protocols helped servers identify the validity of a sender, but they did not allow the sender to define what would happen if the sender was not found to be valid, which prevented domain owners from controlling the use of their brand.
What is Sender Policy Framework or SPF?
Since we mentioned DEMARC is built upon Sender Policy Framework or SPF we feel we should provide you with its meaning. SPF is an open standard protocol that allows domain owners to create a list of approved email senders. It provides an additional security layer for domain owners as it prevents malicious or bad actors from using their domain for sending phishing emails.
With an authorized sender list in place, the recipient server verifies the details of the received emails with the practices put in place and approves them accordingly. A document called the SPF record contains instructions on what to do with the emails. If the email sender details do not appear in the list of authorized senders, the email is considered to be a phishing email and is rejected or sent back. This method decreases the likelihood of spam or malicious messages passing through the server.
What is DomainKeys Identified Mail or DKIM?
Now let us cover DomainKeys Identified Mail or DKIM. DKIM is an email authentication method designed to detect forged sender addresses in email, a technique often used in phishing and email spam. DKIM allows the receiver to check that an email claimed to have come from a specific domain was indeed authorized by the owner of that domain. It achieves this by affixing a digital signature, linked to a domain name, to the header of each outgoing email message. The recipient system can verify this by looking up the sender's public key published in the DNS record. A valid signature also guarantees that some parts of the email (possibly including attachments) have not been modified since the signature was affixed. Usually, DKIM signatures are not visible to end-users and are affixed or verified by the infrastructure rather than the message's authors and recipients.
In conclusion
DEMARC is an automated email authentication and reporting protocol designed to increase email security by ensuring the authenticity of the sender’s identity. Built upon the industry standards SPF and DKIM protocols, DEMARC protects a domain from being used by bad actors in an email attack such as spoofing, phishing, and spamming. The protocol helps make certain that the listed sender is a trusted source and who they are supposed to be and provides the receiving server instructions on what actions to take, be it, accept the message, quarantine it, or reject it based on policies the sender defines.