Benefits Of DMARC
As the DMARC (Domain-based Authentication Reporting and Conformance) standard continues to mature, more organizations than ever before are implementing it to protect their customers and their brand from email fraud.
DMARC helps ensure that legitimate email is properly authenticating against established DKIM (DomainKeys Identified Mail) and SPF (Sender Policy Framework) standards and that fraudulent activity appearing to come from domains under a brand’s control is blocked.
With DMARC, senders can instruct email providers on how to handle unauthenticated mail via a DMARC policy. Senders can either:
Monitorall mail to understand their brand’s email ecosystem without impacting the delivery of messages that fail DMARC
Quarantinemessages that fail DMARC (e.g., move them to the spam folder)
Rejectmessages that fail DMARC (e.g., never deliver the message to the inbox)
But implementing DMARC can get complicated quickly. Here are the three most common DMARC implementation challenges and ways to mitigate them.
Challenge 1: Identifying the right resources
Email security is not the responsibility of a single person or team. From my experience working with some of the world’s largest brands, I have found that the most effective DMARC implementations involve a combination of teams and resources.
They can include security, fraud prevention, marketing, incident response, DNS administrators, mailstream owners, vendors, and others. The more teams you can identify up front who have a vested interest in email security, the better you will position your organization for success.
Ask around and you might be surprised to learn how many of your colleagues are, in fact, dependent on email security and the benefits it provides.
Challenge 2: Getting visibility into your email ecosystem
Enterprise organizations often have complex email ecosystems, which makes it difficult to both uncover authentication issues and understand who is sending legitimate email on behalf of the brand.
Setting a DMARC policy to “monitor” mode grants the visibility you need to make informed policy decisions. You will learn what domains and vendors are sending mail on your behalf, which messages are authenticating, which messages are not, and why.
DMARC’s “monitor” mode simply instructs email providers like Gmail to send your company information on what is happening to your email. It does not instruct email providers to block messages that fail DMARC or send those messages to the spam folder.
To begin receiving information about how your email is sending and authenticating, create TXT records in your DNS for your domains. Then, consume and parse the DMARC reports. Making sense of these reports on your own can be a challenge, which is why many companies choose to work with a vendor like Return Path. When you have this email data, you can identify authentication problems to address.
Challenge 3: Knowing when to enforce policy
Determining exactly when you should move from DMARC’s “monitoring” mode to “reject” (when all emails failing DMARC get blocked from the inbox) is a common question.
The answer? It depends on the domain. All email is not created equal. Promotional mailings, transactional emails, regulatory emails, and others need to be segmented and handled differently. Conduct an audit of your domains, prioritize them, and assess risk, both in terms of security and deliverability.
If you are working with a vendor, they can help. At Return Path, for example, we offer a dashboard which analyzes authentication results for each domain, suggests authentication action items, and notifies users when their domains are ready for policy.
The benefits DMARC provides—granting visibility into your email program and protecting your customers and your brand from email fraud—far surpass the initial challenges of implementation. It is worth the upfront effort.
How can I tell if DMARC is making a difference?
A day or two after a domain owner publishes the simplest monitoring-mode DMARC record in DNS, they will begin to receive reports from DMARC receivers with statistics about email sent to them using the domain owner’s domain. In other words, if you own or operate example.com and publish a DMARC record requesting reports, you will get statistics on all messages that claim to come from your domain from all DMARC receivers. So, you will suddenly be able to see how many fraudulent messages are using your domain, where they’re coming from, and whether or not they would be stopped by a DMARC “quarantine” or “reject” policy. The report from each receiver is an XML file that includes the following fields:
Every IP address using your domain to send email
A count of messages from each of those IP addresses
What was done with these messages per the DMARC policy shown
SPF results for these messages
DKIM results for these messages
www.dmarcsonar.com client portal provides reports which provide a great deal of insight into the health of your message streams.
DMARC – Usage and limitation
DMARC is a great solution for preventing direct domain spoofing. When an email is sent by an unauthorized sender (whether it is sent by a malicious user, or even an unauthorized user of a department of the company that owns/operates the domain), DMARC can be used to detect the unauthorized activity and (if so configured) request that those messages be blocked or discarded when they are received.
If the owners/operators of website.com use DMARC to protect that domain, it would have no effect on website.net, unless .NET is also DMARCISED
Impersonating a given domain is a common method used for phishing and other malicious activities, there are other attack vectors that DMARC does not address.
DMARC does not address cousin domain attacks (i.e. sending from a domain that looks like the target being abused – e.g. website.com vs websit3.com ), or display name abuse where the “From” field is altered to look as if it comes from the target being abused.
People and companies around the world suffer from the high volume of spam and phishing on the Internet. Over the years several methods have been introduced to try and identify when mail from (for example) myrealcompany.com really is, or really isn’t coming from myrealcompany.com. However:
These mechanisms all work separately and isolated from each other
Each receiver makes own decisions about evaluation of the results
The legitimate domain owner (e.g – myrealcompany) never gets any feedback
DMARC addresses the above short falls by providing coordinated, tested methods for:
Domain owners to:
Signal that they are using email authentication (SPF, DKIM)
Provide an email address to gather feedback about messages using their domain –wether legitimate or not
A policy(report, quarantine, reject) to apply to messages that fail authentication
Email receivers to:
Be sure that a given sending domain is using email authentication
Consistently evaluate SPF and DKIM along with what the end user sees in their inbox
Determine the domain owner’s preference (report, quarantine or reject) for messages that do not pass authentication checks
Provide the domain owner with feedback about messages using their domain
DMARC is best implemented slowly (have u heard of a tree that has grown in a day 😛 ?)
A domain owner who has deployed email authentication will begin using DMARC in “monitor mode” to collect data from participating receivers. As the data shows that their legitimate traffic is passing authentication checks, they will change their policy to request that failing messages be quarantined. As they grow confident that no legitimate messages are being incorrectly “quarantined”, they will move to a “reject” policy.
What is DMARC and how it can help us?
DMARC, which stands for “Domain-based Message Authentication, Reporting & Conformance”, is an email authentication protocol. It builds on the widely deployed SPF and DKIM protocols, adding a reporting function that allows senders and receivers to improve and monitor protection of the domain from fraudulent email.
DMARC makes it easier for email senders and receivers to determine whether or not a given message is the real email from the sender, and what to do if it isn’t. DMARC makes is easier to identify spam and phishing messages, and keep them out of users, customers and email inboxes. DMARC allows email senders and receivers to cooperate in sharing information about the email they send to each other
If you want to remove the threat of direct domain spoofing, prevent spear phishing attacks the you must implement DMARC