New filters may thwart spammers

Upgraded e-mail filters installed Tuesday may dramatically decrease the amount of spam reaching Yale mailboxes, a preliminary analysis suggests.

During a one-day test last Friday, filters with the revamped software caught 30 percent more spam than did the filters that Yale has been using until now, Chief Information Officer Philip Long said. If the test proves accurate, Information Technology Services may be able to curb the flood of junk e-mail that attacked University accounts over the summer.

Long said that data from a single day is not enough to declare victory, and that it will take several weeks to verify the filters’ impact. Anecdotal evidence from students and staff suggests that the new measures led to a significant decrease in spam, though not necessarily for all users.

“I have personally noticed the difference in my own inbox as well as in my local junk e-mail filter, so I’m persuaded this is a big change even without having several weeks of data,” Long said.

The upgrades come at the close of a painful summer for e-mail junkies. The amount of spam targeting Yale inboxes increased by about a third between April and June, the last month for which statistics are available. Currently, ITS officials estimate that about 70 percent of incoming e-mail is discarded as spam.

Several students said their spam levels have decreased since the start of school. Valerie Gordon ’09, one of many students who was spammed through a Yale panlist during the summer, said the influx has now stopped.

“Every time I checked my mail, I saw a message and it turned out to be nothing,” she said. “I haven’t received the spam e-mail in the last few days, so it seems like a total improvement.”

Long attributed the summer’s spike to rising levels of spam throughout the Internet, which he said has resulted from an increase in the number of smarter spammers. The filters’ effectiveness will erode as spammers continue to invent new avenues of attack, though a second upgrade may occur by the end of September, Long said.

The planned upgrade, which is currently in a test phase, will for the first time target spam hidden in image files attached to messages.

ITS is proceeding carefully so as not disrupt the delicate system, Long said.

“This filter has to process every single piece of mail,” he said. “We do a lot of performance testing around changes to something that has millions of transaction a day.”

The filters in question are a second line of defense in a multi-tiered system. At the first level, about half of incoming e-mail is automatically discarded because it comes from sources known to be dubious. Then server filters scan the remaining messages for spam and viruses.

Long said the upgrades will probably have the greatest impact on users who receive more spam. But a few students, including those with large spam volumes, said they did not experience a change.

“I’ve been getting a ton of spam, and I have not noticed a decrease at all,” Lissa Yu ’08 said.

Another measure expected to help combat spam — to a lesser extent — was the elimination of automatic e-mail aliases in August. Under the former system, a message sent to an address that closely resembled a Yale e-mail account was rerouted to that account. Sending an e-mail to phil.jackson@yale.edu, for example, would work just as well as sending it to philip.jackson@yale.edu. Now, if users wish to use an e-mail alias, they must register it with ITS. The change, which was put in place to eliminate ambiguities in Yale’s e-mail directory, may cut down on duplicate spam messages sent to different but similar addresses.

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