Friday, February 23, 2007

Spam War is Lost?

Having more than a passing interest in the subject, this article raised some interesting issues.

MOST internet users already know it: spam is on the rise again as senders of unwanted email find new ways to circumvent filtering systems.

A study released last month by the security firm Postini found that unwanted messages now account for 91 per cent of all email, and over the past 12 months the daily volume of spam rose by 120 per cent.

A separate report by California-based IronPort Systems concluded that worldwide spam volumes increased from 31 billion messages daily in October 2005 to 61 billion messages per day in October 2006.

Security experts cite two key reasons for the surge, which has come after a brief respite in which spam appeared to be stabilising.

First, spammers are using massive networks of hijacked computers called "bot-nets" to send the emails. Mr Postini said more than one million infected computers are being used for spam and virus attacks each day, with 50,000 or more active at any instant.

Spammers are using more sophisticated techniques to get around filters, notably the use of "image spam".

Image spam reached a new high of 25 per cent of total spam volume in October 2006, an increase of 421 per cent in a year, according to IronPort.

Paul Judge, chief technology officer of Secure Computing, said filters that use key text words, mathematical analysis or even optical recognition have become less effective against the newest spam.

"Spammers are using advanced mathematical and graphical techniques like random modification of image pixels and dynamic construction of images from multiple components to bypass spam filtering tools," he said.

California security firm McAfee said some spammers now use "island-hopping," directing messages from the domain names of small islands to disguise themselves from filters that traditionally catch more well-known domains.

McAfee traced spam activity from the Isle of Man to the tiny tropical island of Tokelau in the South Pacific.

Other areas whose domains are being used include Tuvalu, Tonga, and Sao Tome and Principe.

"This new trend is another example of spammers' relentless quest to spread their abuse of internet domains far and wide," said Guy Roberts, a McAfee researcher. "Some of these islands have dozens of spammed domains per square mile."

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