Average spam message size at record low

No decrease of bandwidth usage as number of spam messages keeps increasing.

The average size of spam messages has decreased to a record low of just over 2KB, security company Marshal reports.

The average size of spam messages was almost 11KB early in 2007, when spammers hid the content of their messages in images and used sophisticated HTML and garbage text to confuse Bayesian filters.

But it seems that spammers have come to the conclusion that these methods have little success in circumventing spam filters and several of the major botnets are now sending out short spam messages containing little more than a few lines of text and a link.

However, system administrators have no reason to expect this to have a positive effect on email bandwidth. A report by email security company Proofpoint states that the amount of spam has risen by 50 per cent in the first quarter of 2008, with some companies reporting an increase of 200 per cent. Proofpoint attributes this growth to new users on the internet.

"Many of these users are not savvy to modern social engineering techniques and also have limited access to virus protection," said Andres Kohn, vice president of product management for Proofpoint. "This makes them easy targets for malware designed to seize control of their computers. We expect this trend, and the commensurate trends in botnet and spam growth, to continue through 2008 and beyond."

An overview of the methods used by spammers can be found in John Graham-Cummings's Spammers' Compendium.

3 April 2008

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