Sophos, a world leader in protecting businesses against viruses,
spyware and spam, has revealed the top ten malware threats and
hoaxes causing problems for businesses around the world during the
month of April 2006.
The report, compiled from Sophos's global network of monitoring
stations, reveals that Netsky-P, which recently celebrated its
second birthday, has returned to the top of the virus chart,
replacing Zafi-B, which Sophos first protected against 22 months
ago. However as a proportion of all malware, email viruses and
worms continue to decline - 86% of the threats discovered by Sophos
during April were Trojan horses, used by hackers to download
malicious code, spy on users, steal information or gain
unauthorised access to computers.
The top ten viruses in April 2006 were as follows:
"While email worms occupy the top spots, it's clear that Trojan
horses represent by far the most prominent threat to IT security,"
Theriault, senior security consultant at Sophos. "Trojans are
constantly being fine-tuned by hackers to catch out specific
targets. As they are likely to be more difficult to identify,
there's a danger that more individuals will make the mistake of
clicking on an unsolicited attachment or a dubious weblink."
In addition, Sophos found that at least 28% of threats reported
during April allow an unauthorized third party to access the
computer remotely - further evidence that hackers are now primarily
motivated by financial or data theft rather than simply to cause
The fact that fewer mass-mailing worms are being created while
cybercriminals are focusing their efforts on smaller, targeted
attacks, has meant that long established threats continue to
dominate the top ten. This proves that many computer users are
still failing to update their protection and remove the risk of
infection from these old nasties.
"It's astonishing that Netsky-P is still going strong 25 months
on, and users with insufficient malware protection must take the
brunt of the blame for giving it this continued lease of life,"
continued Theriault. "While greater education is helping bring some
users up-to-speed on IT security threats, Netsky and Zafi continue
to linger, and many may wonder if Microsoft will strike the killer
blow to these worms when it releases its Windows Vista operating
system in 2007."
Security has long been publicised as the major addition in the
next instalment of Microsoft's widely-used Windows operating
system, however details are still emerging as to how
all-encompassing the new Vista security features will be, or the
potential impact on malware designed for older versions of
"It's important to remember that as older threats are
vanquished, others will undoubtedly take their place," explained
Theriault. "Mass-mailing worms may be in decline, but it's highly
unlikely that they will disappear entirely - the introduction of a
major new operating system may even spark a new wave of threats, as
virus writers try to find holes in the product."
Elsewhere in the virus chart, there are re-entries for two Mytob
variants, Mytob-C and Mytob-AS, while another email worm,
Dolebot-A, enters the chart for the first time in ninth position,
accounting for 2.2% of all viruses reported. Sophos's research
shows that 0.7% or one in 141 emails is viral. The company now
identifies and protects against a total of 121,096 threats, an
increase of 1054 on last month.
The top ten hoaxes and chain letters in April 2006 were as
"It's a return to the top of the charts for the Hotmail hoax
this month, while the Dutch language Music Top 50 chain letter has
grown in prevalence, clogging bandwidth and wasting computer users'
time," said Theriault. "The chain letter purports to be from a new
television programme, and falsely promises a free Discman for
recipients that forward on the email to others. Given that we're
now firmly in the age of the iPod, it's surprising that such
outdated hoaxes continue to fool people - our advice is if an offer
sounds too good to be true, it probably isn't the real deal."
Sophos has made available a free, constantly updated RSS information feed which means users can always
find out about the latest viruses and hoaxes.
Graphics of the above top ten virus chart are also available.
For more information about the latest trends in viruses, spyware
and spam read the in-depth Sophos Security Threat Management Report