Spammers use sender authentication too, study says

IDG News Service - New technology for identifying the sender of e-mail messages hasn't been widely adopted, despite backing from software giant Microsoft Corp., and it may not be effective at stopping spam, according to a survey by e-mail security company CipherTrust Inc.
A check of approximately 2 million e-mail messages sent to CipherTrust customers between May and July showed that only about 5% of all incoming messages came from domains that published a valid sender authentication record using the Sender Policy Framework (SPF) or a newer standard backed by Microsoft called Sender ID. Within that 5%, slightly more is spam than is legitimate e-mail, said Paul Judge, chief technology officer at the Alpharetta, Ga.-based company.
Sender ID is a technology standard intended to close loopholes in the current system for sending and receiving e-mail that allow senders -- including spammers -- to fake, or "spoof," a message's origin. Organizations publish a list of their approved e-mail servers in the Domain Name System. That record, referred to as the SPF record, is then used to verify the sender of e-mail messages sent to other Internet domains using Sender ID.
Tens of thousands of Internet domains have published SPF records since the standard was introduced by Meng Weng Wong, chief technology officer at Pobox.com. In May, Microsoft and Meng reached an agreement to merge SPF with a Microsoft-developed standard called Caller ID to form the new Sender ID standard, which Microsoft submitted to the Internet Engineering Task Force in June for approval.
Sender ID is fast becoming the de facto e-mail authentication standard, as Microsoft rallies support from e-mail providers, Internet service providers and e-mail software vendors. But the survey casts doubt on whether Sender ID or its predecessor, SPF, can put an end to spam, Judge said.
"The idea that SPF would point to legitimate e-mail because spam would fail SPF checks is not true, because spammers have rolled out [SPF] records, too," he said. "In fact, three times more spam passes SPF checks [than] fails it, so passing or failing an SPF check is not a strong indicator that messages are spam."
The problem is that spammers have been faster to adopt the technology than legitimate e-mail senders, Judge said. "Spammers are now better than companies at reporting the source of their e-mail," he said. In fact, of the messages that pass an SPF check, 34% more are spam than legitimate e-mail, according to the CipherTrust survey.

Judge acknowledged that the CipherTrust survey covers only a small sample of the billions of e-mail