Original URL: http://www.theregister.co.uk/2006/04/24/email_authentication_pushed/

Email authentication gaining steam

Sender ID and DomainKeys pushed at anti-spam summit

By Robert Lemos

Posted in Security, 24th April 2006 09:37 GMT

A host of software companies, security firms and internet service providers met in Chicago on Wednesday to urge corporations and bulk message senders to adopt email authentication technologies.

The technologies, known as Sender ID and DomainKeys, aim to allow email recipients to positively identify the sender of an email message and hold the promise of giving service providers the tools they need to effectively end spam and phishing attacks.

Yahoo!, the creator of DomainKeys, receives about a billion messages a day signed with the technology though Yahoo! Mail, the company said. Meanwhile, more than 2.4m domains are publishing the additional domain information required for Sender ID, up from 20,000 two years ago, according to Microsoft, which has spearheaded the Sender ID initiative. In total, more than 35 per cent of email is authenticated in some way and 21 per cent of Fortune 500 companies publish Sender ID records, according to Microsoft.

Considering that both authentication technologies modify current email practices in some way, that's solid progress, said Craig Spiezle, director of the technology care and safety group at Microsoft and the chairman of Wednesday's Email Authentication Summit.

"This process is a 747 in mid-flight," Spiezle said "You want to make these modifications to the infrastructure but you don't want to bring it down. The whole goal here is minimal cost and effort."

The summit marks the passage of a two year deadline promised by Bill Gates in January 2004, by which spam would cease to be a problem for internet users. While Microsoft has missed the target, if the boosterism represented by the summit continues to work and adoption grows, then internet service providers will have credible tools to help significantly reduce the amount of spam appearing in customer inboxes.

"This is like the telephone problem - no one wants to have the first one," said Eric Allman, chief science officer for email server software maker Sendmail. "But we are seeing a lot of people who want some sort of technology to solve the spam problem."

The summit also marks the comeback for Sender ID and an evolutionary step for DomainKeys. About 18 months ago, Microsoft's efforts to push forward the standard almost came to naught, when the Internet Engineering Task Force (IETF), the net's technical standards body, rejected the company's proposal over patent issues. Domain Keys, supported by Yahoo!, is in the process of being merged into another technology proposed by Cisco Systems, to create DomainKeys Identified Mail.

Email authentication does not solve the problem of unsolicited commercial email but provides a tool to end the spoofing of the sender's address, making the consequences of sending bulk email a reality for spammers.

The two major proposals solve the problem in different ways. Sender ID, based on Microsoft's Caller ID proposal and the Sender Policy Framework (SPF) created by Meng Wong, the founder of email service firm Pobox.com, authenticates email by checking the address of the sending server against a record added to domain name servers. DomainKeys use public-private key pairs to authenticate the message. Like Sender ID, the identifying information - in this case, the public key - is published in a special record stored on domain name servers.

"Authentication is authentication and nothing more," Sendmail spokesperson Allman said, who is also the lead editor of the DomainKeys Identified Mail (DKIM) proposal to the IETF. "It is like a driver's license or a passport. It tells you nothing about my driving record. Spammers can authenticate just like anyone else."

In fact, early studies of junk mail in 2004 found that nearly a sixth used the Sender Policy Framework, the predecessor to Sender ID, to appear legitimate.

However, as more legitimate domains are adopting the technologies, companies are developing reputation systems to evaluate which domains are considered "spammy" and which deliver content that people want in their inboxes. Spammers will not be able to spoof legitimate domains and still authenticate. And, email software can create a list of unwanted mail from a typo domains, such as micros0ft.com, that might otherwise fool the user.

"Authentication is a really big building block in terms of making a more intelligent determination of what is spam and what is not," said Ken Schneider, chief architect for Symantec and former chief technology officer at email security provider Brightmail (Symantec owns SecurityFocus). "If you are tracking reputation on top of this stuff, then it gives you the tools to detect attacks."

The technologies also help defeat phishing attacks, which have grown as an internet problem, Schneider said. In the second half of 2005, one in every 119 emails was identified by Symantec as a phishing attempt.

In a report published on Wednesday, the Email Sender and Provider Coalition found that the major ISPs representing the recipients of more than half the internet's email were using the email authentication technologies in some way.

But this is not a time to ease up on the pressure to adopt the technology, said Microsoft's Spiezle. More education and development is necessary, he said.

"There is no perfect solution right now," Spiezle said. "With any of these approaches, we need to be looking ahead and not at our shadow, because the deceptive forces out there will be looking for new ways to attack."

This article originally appeared in Security Focus.

Copyright © 2006, SecurityFocus