Leading free email providers AOL, Google, Microsoft, and Yahoo have banded together with financial, social media, and message security companies to make it easier to verify the authenticity of email messages.

Together, the companies on Monday announced the formation of DMARC.org, an organization that aspires to make email more trustworthy and phishing more difficult. DMARC.org will promote the DMARC specification, which describes how email senders should authenticate messages, how they should communicate their authentication practices, and how message recipients can discover and implement sender policies.

The acronym stands for domain-based message authentication, reporting, and conformance. Think of it as a set of rules that can make email more secure.

"It's a specification that the DMARC.org group has worked on over the last 18 months to produce," said Google product manager Adam Dawes in a phone interview. "It's a proposed mechanism by which senders and receivers can work together to fight phishing, and to lock down and prevent abuse of domains in the email channel."

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Malicious email senders can easily make their messages appear to come from someone else's Internet domain, and such messages often are used for phishing--attempts to dupe message recipients into providing sensitive information under false pretenses or through malware.

According to the Anti-Phishing Working Group, there are presently about 20,000 to 25,000 unique phishing campaigns every month, each targeting hundreds of thousands to millions of email users. And thousands of fake phishing websites are set up every day.

Those involved in DMARC have a stake in making email a better experience. Dawes said that being duped by a phishing message often leads to compromises at multiple online services, because people tend to use the same password across different websites. Losing control of one's account, he said, "is one of the worst experiences that a user can have. If that happens because someone received a phishing message in his or her Gmail inbox, that's a terrible Google experience. Users rely on us to protect them against those threats."

In addition to AOL, Google, Microsoft, and Yahoo, other organizations participating in the DMARC group include financial companies Bank of America, Fidelity Investments, and PayPal; social media companies American Greetings, Facebook, and LinkedIn; and email security companies Agari, Cloudmark, eCert, Return Path, and Trusted Domain Project.

To fight phishing, various forms of email authentication are available, such as SPF, DKIM, and Sender ID. But there's no common standard. As a result, companies that authenticate their email have to coordinate with email providers to make sure that everyone is on the same page when it comes to which messages should be discarded for lack of authentication. PayPal began doing this with email providers in 2007, but approaching each email provider individually isn't ideal. DMARC isn't intended to replace existing specifications, but rather to tie them together.

"We view this as adding significant value to SPF and DKIM," said Microsoft engineer Paul Midgen.

The DMARC framework offers a way to formalize and automate message authentication processes and reporting so that security scales.

"What DMARC now allows is for any domain owner to have control over unauthenticated messages in the Gmail inbox," said Dawes. And the same holds true for inboxes operated by other email providers.

Agari, an email security provider, implemented DMARC last year and subsequently partnered with AOL, Google, Microsoft, and Yahoo. The company's Email Trust Fabric adds value to DMARC by turning raw DMARC data into actionable reports, to help companies understand their email infrastructure and message deliverability. Agari claims it has rejected approximately 4 billion threat messages since the technology was initially deployed in January 2011.

"For me, Monday is going to be one of the most auspicious days in the history of Internet security," said Agari founder and CEO Patrick Peterson in a phone interview in advance of DMARC's launch. "People will be able to send a message and recipients will be able to know where it came from."

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