Anti-Spam Technical Alliance Publishes Industry Recommendations to Help Stop Spam

SUNNYVALE, Calif., REDMOND, Wash., ATLANTA, and DULLES, Va., June 22, 2004 — The Anti-Spam Technical Alliance (ASTA), whose participants include Yahoo! Inc. (Nasdaq YHOO), Microsoft Corp. (Nasdaq MSFT), EarthLink (Nasdaq ELNK) and America Online Inc. (NYSE TWX), today unveiled the result of more than a year of close collaboration by presenting a host of detailed best practices and technical recommendations for the entire industry in an effort to fight the scourge of spam.

The proposal provides recommended actions and policies for Internet service providers (ISPs) and e-mail service providers (ESPs) as well as large senders of e-mail including governments, private corporations and online marketing organizations. These recommendations primarily focus on two key issues: helping solve the e-mail forgery problem by eliminating domain spoofing through Internet Protocol (IP)-based and signature-based solutions; and best practices to help prevent ISPs and their customers from being sources of spam.

The complete ASTA proposal can be found at each adopting companys Web site:

ASTA was founded in April 2003 to bring together key industry stakeholders to drive technical standards and promote collaboration in the development of industry guidelines to address the spam problem. Current members include leading technology companies such as America Online, British Telecom, Comcast, EarthLink, Microsoft and Yahoo!


With these proposed solutions, ASTA is taking a huge step toward collective and enforceable technologies in reducing spam and e-mail forgery, said Brad Garlinghouse, vice president of Communication Products at Yahoo! Inc. We are laying out clear best practices and Good Neighbor policies that will help change the rules of the game on spammers once and for all.

We believe that thanks to continued innovation and the ongoing cooperation of governments and industry around the world, we are on the right path to turn the tide against spammers but further change is needed on an industrywide basis to thoroughly contain the problem for consumers and businesses worldwide, said Ryan Hamlin, general manager of the Anti-Spam Technology & Strategy Team at Microsoft. Our aim with this proposal is to help lay out a clear framework for the industry as we continue to work together to end the spam business and put our customers back in control of their inboxes once again.

Todays announcement shows the industrys commitment to working together to develop the best technical standards and practices that all providers can use to stop spam, said Linda Beck, executive vice president of Operations at EarthLink. By collaborating on new ways to better identify the origin of messages, we can help lift the veil of anonymity on spammers and restore the integrity of e-mail. We encourage continued testing and public discussion in order to move toward industry-standard technical solutions.

This announcement opens an entirely new chapter in spam fighting on behalf of all online consumers. Spam is an industrywide challenge that merits an industrywide solution. Creating a set of best practices puts us on a clear glide-path to winning a major battle against spammers, scammers and spoofers, said Matt Korn, executive vice president, Network & Data Center Operations at America Online. This proposal also shifts the spam fight toward identifying legitimate senders of e-mail to ensure prompt delivery of their e-mail. Now were going to focus on testing and evaluating cost-effective technologies that can identify legitimate senders of e-mail and help restore consumer trust in their e-mail inboxes.

About Yahoo!

Yahoo! Inc. is a leading provider of comprehensive online products and services to consumers and businesses worldwide. Yahoo! is the No. 1 Internet brand globally and the most trafficked Internet destination worldwide. Headquartered in Sunnyvale, Calif., Yahoo!s global network includes 25 world properties and is available in 13 languages.

About Microsoft

Founded in 1975, Microsoft (Nasdaq MSFT) is the worldwide leader in software, services and solutions that help people and businesses realize their full potential.

About EarthLink

EarthLink revolves around you (TM). Celebrating ten years as a leading national Internet service provider (ISP), Atlanta-based EarthLink has earned an award-winning reputation for outstanding customer service and its suite of online products and services. According to the J.D. Power and Associates 2003 Internet Service Provider Residential Customer Satisfaction Study(SM), EarthLink is ranked highest in customer satisfaction among high-speed ISPs. Serving more than five million subscribers, EarthLink offers what every user should expect from their Internet experience: high-quality connectivity, minimal drop-offs and ISP-generated intrusions, and customizable features. Whether it’s dial-up, high-speed, Web hosting, or wireless Internet service, EarthLink provides the tools that best let individuals use and enjoy the Internet on their own terms. Learn more about EarthLink by calling (800) EARTHLINK or visiting EarthLinks Web site .

About America Online

America Online Inc. is a wholly owned subsidiary of Time Warner Inc. (NYSE: TWX). Based in Dulles, Virginia, America Online is the worlds leader in interactive services, Web brands, Internet technologies and e-commerce services.

America Online is a registered trademark of Time Warner, Inc.

EarthLink and the EarthLink logo are registered trademarks of EarthLink Inc.

Microsoft is a registered trademark of Microsoft Corp. in the United States and/or other countries.

Yahoo! and the Yahoo! logo are trademarks and/or registered trademarks of Yahoo! Inc.

The names of actual companies and products mentioned herein may be the trademarks of their respective owners.

For more information, press only:

Mary Osako, Yahoo!, (408) 349-6255, [email protected]

Rapid Response Team, Waggener Edstrom for Microsoft, (503) 443-7070, [email protected]

Carla Shaw, EarthLink, (404) 748-7267, [email protected]

Nicholas Graham, America Online, (703) 265-1746

Summary of ASTA Recommendations

ASTAs proposal focuses on two key issues: helping solve the e-mail forgery problem by eliminating domain spoofing through IP-based and signature-based solutions, and best practices to help prevent ISPs and their customers from being sources of spam.. Recognizing that broad adoption of any technology or best practice is critical to solving the spam epidemic, all members of ASTA have agreed to the following recommendations:

Addressing E-mail Address Forgery

One of the key problems with todays e-mail infrastructure is that messages do not contain enough reliable information to enable recipients to decide whether an e-mail message is legitimate and reliably identify the sender. Spammers take advantage of this fact and commonly disguise the origin of their messages by forging the sender addresses on their e-mail using someone elses domain name. This is called domain spoofing.

Although the problem of identifying the origin of e-mail is complex, there are two promising new methods that organizations can implement to lay a foundation for future advances and promote authentication that verifies that senders of a message is who they claim to be:

  1. Currently, the only trustworthy attribute in an e-mail message header is the IP address of the server that is transmitting the e-mail. IP addresses can therefore be used by e-mail receivers to verify other attributes in the message header, such as the sending domain, and thus help reduce the common forms of phishing and forgery that are rampant today. This verification loop can be done using the existing Domain Name System (DNS) infrastructure combined with fairly simple changes to the receivers e-mail systems.

  2. Another approach to sender authentication uses a technology called Content Signing (CS). CS systems use public/private key pairs to generate the signatures that are used for sender verification. The public keys may be made broadly available through a variety of key exchange mechanisms or via publication in a directory or in DNS. The private keys are stored securely on the domains mail servers. When a user sends an e-mail message, the mail server uses the stored private key to automatically generate a digital signature for the message. When the recipients mail server receives the e-mail message, it retrieves the senders public key and uses it to verify the digital signature in the message. This verifies both the senders identity and the integrity of the message body (that the e-mail content was not modified during delivery). As with IP-based sender authentication, the companies believe that content signing technologies are an important component of a long-term industry solution.

Throughout the process of implementing these technologies, ASTA members will provide feedback that along with other industrywide feedback will enable subsequent improvements to the specification to be completed, with the goal of providing for the best long-term, industrywide IP based authentication solution.

It is the belief of this group that the ubiquitous deployment of some or all of these proposals, combined with the most innovative anti-spam filtering technologies and approaches, continued litigation against the worst offenders, appropriate legislation and other measures, will serve to reduce the economic incentives and eliminate the entry points for spammers to continue their barrage of unwanted communications. ASTA looks forward to the community response to this proposal and invites participation from all segments of the community to assess the validity and impact of these proposed solutions and their accompanying technical specifications.

Addressing Spam Through Best Practices

In the proposal, ASTA recommends a number of best practices that organizations should implement as applicable. Many of these practices have already been adopted by responsible organizations using e-mail today, but broader global adoption is necessary, as the combined effect of implementing these approaches can serve to minimize opportunities for spammers. Those who do not adopt these proposals risk loss of online user confidence in the safe and trusted exchange of e-mail for the entire community.

Specifically, ASTAs proposal outlines the following:

  • Recommendations for ISPs and mailbox providers and organizations that provide Internet connectivity, such as these:

  • Block or Limit the use of Port 25

  • Implement rate limits on outbound e-mail traffic

  • Control automated registration of accounts

  • Close redirectors that can be abused

  • Close all open relays

  • Configure proxies for internal network use only

  • Detect compromised computers (zombies)

  • Educate users to increase use of existing tools

  • Develop effective complaint reporting systems

  • Recommendations for legitimate bulk e-mail senders, such as these:

  • Do not harvest e-mail addresses through SMTP or other means (defined as collecting e-mail addresses, usually by automated means) without the owners affirmative consent.

  • Register your e-mail domain with a creditable safelist provider.

  • Always provide clear instructions to customers about how to unsubscribe or opt-out of receiving e-mail. Promptly respond to these requests.

  • Do not use or send e-mail that contains invalid or forged headers.

  • Do not use or send e-mail that contains invalid or nonexistent domain names in the From or Reply-To headers.

  • Do not employ any technique to hide or obscure any information that identifies the true origin or the transmission path of bulk e-mail.

  • Do not use a third partys Internet domain name or allow mail to be relayed from or through a third partys equipment without permission.

  • Do not send e-mail that contains false or misleading information in the subject line or in its content.

  • Monitor SMTP responses from recipients mail servers. Promptly remove all e-mail addresses for which the receiving mail server responds with a 55x SMTP error code (e.g., user doesnt exist).

  • Recommendations for consumers, such as these:

  • Install firewalls on PCs as appropriate.

  • Use anti-virus software and other screening tools to detect incoming viruses, malware, and harmful or suspicious code.

  • Make use of spam filtering technologies and customize settings that provide the appropriate level of protection needed.

Some of these recommendations are already part of laws in various countries including the Controlling the Assault of Non-Solicited Pornography and Marketing (CAN-SPAM) Act of 2003 in the United States. However, the disparity between laws and the absence of anti-spam laws in most countries means the industry needs to come together and adopt consistent policies and practices that drive spammers out of business.

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