Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a system that combines the Sender Policy Framework (SPF) and Domain Keys Identified Mail (DKIM) to assess the validity of an email message. Its purpose is to provide email domain owners with the option to safeguard their domain from unlawful usage, often known as email spoofing. The primary goal and effect of DMARC implementation are to protect a domain from being used in corporate email compromise attacks, phishing emails, email scams, and other cyber threat activities.
After the DMARC DNS(Domain Name System) entry has been published, any receiving email server may authenticate the incoming email using the instructions issued by the domain owner within the DNS entry. If the authentication is successful, the email will be delivered and may be trusted. If the email fails the check, it may be delivered, quarantined, or denied based on the instructions included in the DMARC record.
To avoid email misuse, the DMARC standard was initially issued in 2012.
Several industry heavyweights collaborated to develop the DMARC specification. PayPal built it in collaboration with Google, Microsoft, and Yahoo!. These industry leaders collaborated to create an operational specification to achieve official standards.
Based on the existing email authentication mechanisms (SPF and DKIM), they developed the DMARC standard (Domain Keys Identified Mail).
DMARC was created initially as an email security mechanism.
DMARC was mostly used by security specialists in the finance industry.
Since then, DMARC acceptance has grown and extended across the internet environment. DMARC is becoming increasingly popular at this stage.
By prohibiting malicious activity from misrepresenting your domain in emails, DMARC is a vital step in securing the domain and brand.
It may also boost the sender's reputation scores, which can boost deliverability rates.
DMARC increases the trust that the sender's domain is correctly reported in the "header from."
Adopting DMARC encourages an industry standard for dealing with unauthenticated emails, safeguarding all email users against faked harmful communications.
DMARC depends on the well-established Sender Policy Framework (SPF) and Domain Keys Identified Mail (DKIM) standards for email authentication. It also uses the well-established Domain Name System (DNS). In general, the DMARC certification procedure goes as follows:
1. A domain administrator publishes the policy that defines the domain's email authentication processes and how receiving mail servers should handle mail that breaches the policy. This DMARC policy is included in the domain's overall DNS records.
2. When an email is received, it consults DNS to determine the DMARC policy for the domain specified in the message's "From" (Request for Comments (RFC) 5322) header. The message is then checked and evaluated by the incoming server.
3. With this information, the server can determine whether to accept, deny, or otherwise flag the email message by the transmitting domain's DMARC policy.
4. The receiving mail server will notify the sender domain owner of the outcome after applying the DMARC policy.
DMARC uses DNS to broadcast information about how a domain's email should be treated (e.g., do nothing, quarantine the message, or reject the message). Because DNS is used, practically all email systems can determine how email, sent from your domain, should be treated. This element also simplifies deployment because it just takes one DNS update to set up (through a DMARC (TXT-text message) record).
If DMARC enforcement is not deployed successfully in an organisation, domain owners will get notifications on malicious IPs(Internet Protocol) attempting to spoof their domain, but they will be unable to stop domain abusers and impersonators.
No, DMARC cannot work without SPF. DMARC demands not only SPF or DKIM PASS but also the domains utilised by those two protocols.
With a DMARC "p=reject" policy, one may assure that every malicious email is blocked.
While DMARC is not a vulnerability, failing to completely install it leaves your domain exposed to impersonation and phishing attempts.
Twitter adopted DMARC in 2013.