Over 100,000 Sources of Spam and Other Malware Detected in Any Given Hour - Many Zombies   5/17/2005 - 568 views,

SAN MATEO, Calif., May 17 /PRNewswire/ — Mail-Filters.com, Inc. is the
global leader in OEM anti-spam solutions providing technology for its OEM
partners filtering billions of messages a day in more than 100 countries and
30 languages. Mail-Filters noted that last week the number of unique, active,
significant spam sources averaged 103,967 hourly.

“It must be stressed, however, that these sources are just the tip of the
iceberg,” says Ben Westbrook, CEO of Mail-Filters. “The number of machines
detected sending any spam is significantly larger. Given that the typical
number of spammers in any given hour is in the hundreds, we can say that the
vast majority of these machines are hijacked. Not only that, this is a one
hour snapshot of spammers sending messages to our partners’ customers. You can
easily see that millions of computers continue to be hijacked for the purpose
of sending spam and phish.” Mr. Westbrook continued: “The real problem is
that the IP addresses of these innocent hijacked computers get on blacklists
used by some spam filters. Any legitimate mail from these addresses runs the
risk of being stopped, driving up those filters’ false positive rates and
preventing legitimate mail from being delivered to a business associate,
customer, or partner.”

Mail-Filters described in February 2005 the problem with Trojans and the
impact they are having in the email space. Mail-Filters technology is one of
the few anti-spam technologies available in the industry that is not impacted
by these Trojans. Nevertheless, since most spam filters are fooled by this
tactic, spammers and phishers continued to find more effective ways of
hijacking computers for the purpose of sending spam and phishing messages.
This latest data shows the practice is still going strong.

Mail-Filters’ anti-spam filtering technology catches both spam and
phishing messages. It combines two proprietary weapons: the Bullet Signature
Database created and maintained by both technology and human editors, and the
STAR Engine that detects spammer tricks. This approach allows it to catch new
types of spam, including phishing, embedded content, HTML, and foreign
language spam. The result is a catch rate of more than 95% with less than 1 in
1,000,000 false positives.