Panda ActiveScan List of Top Viruses for August 2003

In August, Blaster was recorded as the virus affecting most computers, according to the data gathered by Panda ActiveScan. This worm, which first appeared on August 12, has taken over from Bugbear.B at the top of the list of Top Ten viruses most frequently detected by Panda Software’s free online antivirus solution. Blaster has even infected more computers than Sobig.F, a worm that first appeared in August and which was the most widespread malicious code until now.

According to the data gathered by Panda ActiveScan, Blaster caused, over the last month, more than eight percent of the incidents reported, followed by Bugbear.B (5.34%), Klez.I (3.15%); Sobig.F (3.07%) and Parite.B (2.62%). Trj/PSW.Bugbear.B, Fortnight.E, Enerkaz, Bugbear.B.Dam and Trj/JS.NoClose hold the last five positions of the Top Ten ranking for August.

The most notable development in this month’s report include:

– Indisputable dominance of Blaster, even over Sobig.F
Although Sobig.F is the most widespread malicious code ever (largely due to its capacity to send itself out every ten seconds as ‘spam’, through the computers it affects), Blaster has been the malicious code that has infected most computers.

Among the characteristics that explain Blaster’s dominance, Luis Corrons, head of Panda Software’s Virus Lab, highlights its capacity for “infecting computers without user intervention, such as opening an e-mail or a file attached to a message”. Blaster moves along the Internet searching for computers in order to attack them. When the worm finds these computers, it tries to enter the system through the communications port 135, with the aim of causing a buffer overflow.

– Spreading via vulnerabilities.
Blaster was the first worm to spread by exploiting the RPC DCOM Windows vulnerability. This type of behavior has already been successfully used by other malicious codes in the Top Ten list, such as Bugbear.B and Klez.I. These two worms also use security problems in widely used programs in order to attack as many computers as possible. Again, the presence of this viruses in the ranking, highlights the fact that many users have not applied the updates provided by manufacturers in order to solve these vulnerabilities.

– Increasing activity of Klez.I as it rises to third place from sixth in the last month’s ranking.

Virus % frecuency
W32/Blaster 8.27
W32/Bugbear.B 5.34
W32/Klez.I 3.15
W32/Sobig.F 3.07
Parite.B 2.62
TRj/PSW.Bugbear.B 2.47
JS/Fortnight.E 2.27
W32/Enerkaz 2.05
W32/Bugbear.B.Dam 1.83
Trj/JS.NOClose 1.08

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