Retracing spam steps could halt mass emails
The deluge of spam that pours into email inboxes each day could by curtailed using software that learns to identify the routes taken by unwanted messages, researchers say.
A team from IBM and Cornell University in New York state, US, developed the anti-spam technique, which they call "SMTP Path Analysis". It involves examining information embedded in email messages about the route it has taken across the internet. This allows it to make a good guess as to whether or not a new message is electronic junk mail.
The algorithm at the heart of SMTP Path Analysis studies Simple Mail Transfer Protocol (SMTP) information, which is added to an email message "header" as it is passed between servers on the internet. This remains hidden when a message arrives in a recipient's inbox but can be used retrace its steps between different mail servers.
Most spam filters try to catch spam by looking at the content of a message, rather than its hidden header. Many already learn to identify new spam by examining previous message. But spammers are constantly coming up with new tricks in an effort to outwit such content-filtering techniques.