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DMARC helps protect reputation of American Greetings' e-cards

E-card company American Greetings has turned to DMARC as a way to authenticate its email and protect its corporate name from being sullied by spammers and phishers.

That's not surprising given that the company helped develop DMARC (domain-based message authentication, reporting and conformance), but it has enlisted a DMARC collaborator to carry out the effort.

Rather than build its own infrastructure, the e-card vendor hired Agari, a 2-year-old company that helped write DMARC and now offers it up as a cloud-based service.

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As part of the service, Agari analyzes the data gathered about American Greetings by major email providers that also support DMARC -- AOL, Google, Microsoft and Yahoo -- as well as trends gleaned from data gathered about other Agari customers, says Daniel Raskin, vice president of marketing for Agari.

DMARC layers policy enforcement atop two established spam/phishing detection schemes so emails that fail authentication can be flagged, quarantined or blocked. That can prevent emails with spoofed domains from ever being delivered, thereby cutting down on the incidents of malicious activity that become associated with brand names and hurt business.

That is good for American Greetings because DMARC interferes with very little legitimate email and is a mechanism for preventing emails that spoof the company's domain from reaching end users, says Michael Hammer, Web operations security manager for the company. "The concrete benefit to any recipient of email from our domains is that they can now ask their ISP or Mail Administrator to validate mail originating from our domains (and an increasing number of other organizations' domains) to determine if it really came from our domains," Hammer says in an email response to questions.

DMARC doesn't actually determine whether email is spam; it determines whether email passes authentication as carried out by sender policy framework (SPF) and DomainKeys identified mail (DKIM), two established methods.

SPF allows administrators to specify which devices in their domain are allowed to send email, and leaves a message to that effect in the domain name system (DNS). Recipients of email can check with the DNS to find out whether senders are authorized to send from a particular domain. If they are not, the recipient may choose not to reject those messages.

SPF-protected domains are less attractive to spammers because their spam is more likely to be detected and rejected.

DKIM is a means of digitally signing an email that can be verified using the sender's public key that can be retrieved from the DNS. The idea is to force spammers to use their real source domain, meaning that more accurate filtering of offending domains can be set up. An example of DKIM in use is that Google's Gmail will reject email from PayPal if it can't be verified via DKIM.

DMARC checks whether email passes either or both SPF and DKIM.

While it goes a long way toward reducing certain classes of malicious email, DMARC isn't a cure-all. For example, it doesn't stop emails sent from domains with names that are similar to but different from legitimate domains. But DMARC does reduce the volume of suspicious emails by catching those that come from the legitimate domain.

Hammer says the DMARC analysis American Greetings gets from Agari helps to identify abusive email sooner and to enable quicker takedowns of potentially malicious websites. Hiring Agari removes the need to build a database back end for querying the reports and frees American Greetings from having to write its own analysis software and update it as DMARC evolves.

The company has 16 customers for its DMARC service, not inconsiderable since DMARC was formally launched just four months ago as a suggested industry standard that may be presented to the IETF for formal ratification.

Tim Greene covers Microsoft for Network World and writes the Mostly Microsoft blog. Reach him at tgreene@nww.com and follow him on Twitter @Tim_Greene.

Read more about wide area network in Network World's Wide Area Network section.


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