Sophos, a world leader in protecting businesses against spam and
viruses, has published a report revealing the top ten viruses and
hoaxes causing problems for businesses around the world during the
month of April 2005.
The report, compiled from Sophos's global network of monitoring
stations, shows that Zafi-D, which first appeared at the end of
2004, continues its reign at the top of the list for the fifth
month running, accounting for 46.6% of all reports. Only one new
threat - Mytob-Z - has managed to break into the chart for April,
appearing in seventh place.
The top ten viruses in April 2005 were as follows:
"Old viruses are still taking advantage of poorly protected
computers in April," said Carole Theriault, security
consultant at Sophos. "The Zafi family of viruses accounts for over
50.0% of all the viruses reported to Sophos in the last month.
Perhaps the success of these worms lies in their ability to spread
in multiple languages, catching out unwary users all over the
world. Users should not only be suspicious of unsolicited email in
any language, they should also be ensuring up-to-date anti-virus
protection is in place to thump this virus family on the head."
"Although Mytob-Z only accounts for a small percentage of the
top ten reports, it is the only new worm that has managed to break
into the stronghold of old threats," continued Theriault. "First
sighted in mid-April, Mytob-Z is a nasty piece of work - not only
does it spread ferociously, but it plants a backdoor Trojan horse
which can be used by remote hackers to gain access and control over
a victim's computer. The computer can then be spied upon or used to
send spam or launch denial of service attacks."
Sophos analysed and protected against 1146 new viruses in April.
The total number of viruses Sophos now protects against is 103,269.
Sophos research shows that 2.2%, or one in 46 emails, circulating
during the month of April were viral. This figure is slightly lower
than last month when 1 in 38 emails were viral.
In order to minimise exposure to viruses, Sophos recommends that
companies deploy a policy at their email gateway which blocks
unwanted executable attachments from being sent into their
organisation from the outside world. Companies should also run
up-to-date anti-virus software, firewalls and install the latest
The top ten hoaxes reported to Sophos during April 2005 are as
"While the Hotmail hoax maintains its dominance, there are a
couple of re-entries to the chart this month," said Theriault. "The
mobile phone hoax, first seen in 2000, spreads via email. It is
designed to dupe people into believing that answering a call where
caller information is unavailable will render the mobile unusable.
As ever, this hoax is nonsense, and the best response for computer
users is simply to delete these messages."
Sophos has made available a free, constantly updated information feed for intranets and
websites which means users can always find out about the latest
viruses and hoaxes.
Graphics of the above top ten virus chart are available here.
More information about safe
computing, including anti-hoax policies.