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Spammers continue to beat filters with new URLs
4 August, 2004
Spammers are continuing to utilize 'slippery' techniques
to beat blacklists and spam filters.
That?s the conclusion from anti-spam vendor Commtouch, in
its July analysis of spam patterns and trends. The Commtouch
Spam Detection Center analyzed hundreds of millions of spam
messages in the month of July 2004 and found that 88.42 per
cent were of new origin compared to the previous month. In
addition, 98.17 per cent of the URLs advertised in spam messages
were new compared to the previous month. Those numbers indicate
that 88.42 per cent of the IP addresses used to send spam
messages were new in the month of July.
"The fact that 98.17% of URLs which appear in spam messages
are new indicates that spammers can easily change the content
of an email message and URL despite the associated cost of
registering a new domain. A new, active URL requires domain
registration," said Avner Amram, executive vice president
at Commtouch.
That makes it difficult for some types of anti-spam technologies
to catch the slipper spam, Amram said.
"The fact that spammers are changing the content of
email messages means that a content filtering anti-spam solution
-- like Bayesian, heuristic or URL filtering solutions, which
use static rules or manual learning mechanisms -- are reactive
and will fail over time to handle the problem effectively.?
That, says Commtouch, works to the advantage of its RPD technology,
which blocks spam minutes from the beginning of an outbreak
by analyzing in real-time the recurring patterns of an email
message, as opposed to the content.
In the month of July, Commtouch detected that spam was sent
from 171 countries, as compared to 167 countries during June.
The United States continues to lead as the main origin of
volume of spam, but it dropped to 45.84 per cent of global
spam, compared to 55.69 per cent in the previous month. Mexico
has now joined the top 10 list of countries from which spam
originates, replacing the United Kingdom. South Korea (13.51
per cent) China (9.21) Brazil (3.8), Hong Kong (3.26) and
Canada (3.25) followed the US.
The number of spammer websites hosted in China dropped to
29.97 per cent -- a steep decline from 73.58% during the previous
month. Now, the top five countries find themselves host to
over 99 per cent of spammer websites ? with South Korea, Brazil,
the US and, further back, Hong Kong making up that list.
What percentage of spam is ?legal? under the US CAN-SPAM
law? Less than 10 per cent. Commtouch said that in July, 9.3
per cent of spam messages were CAN-SPAM compliant, meaning
that: the email message has a functioning return email address;
a postal address is included in the sent email message; within
the email message there is an ability for a recipient to 'unsubscribe';
the subject line of the email is not deceptive; and there
is clear and conspicuous identification that the email message
is an advertisement or solicitation.
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