Overall, products’ spam catch rates were significantly lower
than in previous months, in many cases products missed more than
twice as much spam as in previous tests.

"This is a worrying trend," says VB’s Anti-Spam Test Director
Martijn Grooten. "There have been many news stories highlighting
a global decline in spam in recent months, but if spam filter
performances decline too, the situation for the end-user doesn’t
improve at all."

Grooten continued: "It is hard to say what exactly caused
filters to miss more spam, but it looks like spammers are doing
a better job at avoiding IP- and domain-based blacklists. It may
be a sign that they are increasingly using compromised
legitimate systems to send their messages."

The best performance in this month’s test came from Libra Esva,
which blocked 99.97% of all spam messages without blocking any
legitimate mail, and as such was the only product to obtain the
new ’VBSpam+’ award (to qualify for the VBSpam+ award, products
must achieve a spam catch rate that is higher than 99.5% and a
zero false positive rate).

The VBSpam quadrant plots products’ spam catch rate against
their false positive rate, with the top right-hand corner the
area products should be aiming for (with maximum spam catch rate
and minimum false positive rate). The front-runners in this test
can clearly be seen from their positions on the quadrant at
http://www.virusbtn.com/vbspam/charts/vbspam-chart-0312-1200.jpg
(journals and websites are permitted to reproduce this chart
unedited).

The results of the March 2012 anti-spam comparative review can
be seen at http://www.virusbtn.com/vbspam/archive/test?id=173

The full review, including detailed results tables, is available
to Virus Bulletin subscribers or can be purchased as a
standalone review ($19.95)