A quick check of my spam folder over the past two or three months reveals a whole lot more spam than I was getting earlier this year. Promotion of penny stocks seems to be a recurring them, sometimes with ten or more spam messages promoting the same pump-and-dump scheme.
We've known that botnets (highjacking of thousands of individual PCs into a network of drones) has been growing as a channel for spam distribution. Now, it appears that a new trojan, dubbed "SpamThru," has commandeered over 70,000 PCs into another botnet, under direction of Russian hackers.
But whether the volume of spam has increased, or merely the percentage that evade spam filters, is an open question. Ferris Research, quoted in a Datamation article
, believes that spam volume only increased 20% in the fourth quarter of 2006 to date, while the percentage reaching the inbox doubled. Techniques being used by the more sophisticated botnets include use of images instead of text and more compliant response to recipient mail server requests for greylisting.
Unfortunately, spam volume is unlikely to decrease as long as the economic incentives are there. Spam costs very little to send, and even if only a tiny percentage of recipients respond, a penny stock scam can still pay off to the spammer.
The soon-to-be-results of a Computer Economics survey on IT security threats
shows that of all categories of threats, IT security personnel consider spam as one of the most serious.
Like the war on terror, it may never be possible to declare total victory in the war on spam. But it is possible to minimize its impact. A recent Computer Economics study surveys the relative effectiveness of four types of spam-blocking solutions