Spammers have adopted a new standard for email authentication much faster than legitimate emailers, according to a study from security appliance firm CipherTrust published this week
More spam than legitimate email is currently sent using Sender Policy Framework, a recently introduced email authentication protocol. According to CipherTrust’s research, 34 per cent more spam is passing SPF checks than legitimate email because spammers are actively registering their SPF records.
It doesn’t make a lot of sense to make filtering decisions based purely on the fact that the sender is authenticated, so the approach was never going to be a cure-all as we’ve noted before.
As long as spammers comply with the protocol by not spoofing the sender address, their messages will not be stopped by SPF, which CipherTrust has supported since February 2004. CipherTrust’s research among users of its own IronMail message security appliance this summer found that a spam message is three times more likely to pass an SPF check than it is to fail it.
CipherTrust concludes that email authentication protocols like SPF alone are not effective in identifying spam even though they might be useful in curtailing spoofing and phishing attacks. So email authentication protocols aren't a complete waste of time - just ineffective when it comes to holding back the junk mail tsunami. It still advises users to adopt email authentication as part of their fraud and spam prevention arsenal.
Email authentication is in the news after vendors clubbed together to support Sender ID Framework, a protocol which resulted from the merger of SPF and Caller ID, an email authentication protocol proposed by Microsoft. CipherTrust said it would support this unified protocol when it becomes available. ®