The ten most dangerous viruses of 2001

Data compiled by Panda Software shows Sircam and Disemboweler responsible for over 40% of all infections in 2001

MADRID, December 17th 2001

Panda Software, the leading antivirus software producer, has published a list of the ten most prevalent viruses in 2001. The list, based on the number of reported or detected virus occurrences, is compiled using data from the companys technical support services in 45 countries worldwide and from the free online antivirus, Panda ActiveScan.

This years ranking is topped by Sircam (W32/Sircam), which was responsible for more than 24 percent of all infections recorded. Disembowler (W32/Disembowler), also high up on the list, was reported in over 18 percent of cases. The third most frequently detected virus was the multi-faceted MTX(W32/MTX). This virus/worm/Trojan was responsible for more than 12 percent of infections.

The next virus in the list is Hybris. This persistent worm has figured in all Panda Softwares monthly lists of top ten infectors since it was first discovered at the end of last year, and still shows no sign of abating. This year it was responsible for around 10 percent of cases. VBS/Help, otherwise known as Happytime, has also refused to disappear and has been continually infecting computers since last April.

Other malicious code, such as Magistr.B or Navidad.B also figure in the list along with the explosive Badtrans.B, which despite its recent appearance, accounted for more than 5 percent of infections reported throughout the whole year. Nimda.A ranked high despite having only appeared in the latter half of the year and its variant Nimda.D also made the top ten with an occurrence rating of over three percent.

Rank - Name - % of all infections

1 - W32/Sircam - 24.2%
2 - W32/Disemboweler - 18.1%
3 - W32/MTX - 12.5%
4 - W32/Hybris - 9.4%
5 - VBS/Help - 8.3%
6 - W32/Magistr.B@mm - 8.07%
7 - W32/Navidad.B - 5.6%
8 - W32/Badtrans.B - 5.1%
9 - W32/Nimda.A - 5.09%
10 - W32/Nimda.D - 3.3%

This years figures suggest that two clear trends are emerging. Firstly, viruses like Badtrans that cause initially explosive epidemics but then disappear in the course of time and those like Hybris or MTX which maintain a constant level of activity over a long period.

The infection techniques used by the viruses play an important part in determining how persistent a virus will be. Those that use 'social engineering and trick the user into running a file containing malicious code tend to maintain their presence in the list of frequently detected viruses, whilst those like Nimda, which exploit application vulnerabilities, tend to disappear as users apply the corresponding patches.

This year has been marked by the extraordinary virulence of malicious code like Sircam and Nimda, and more recently by the epidemic caused by Badtrans B. The tenacious nature of viruses such as Navidad, which first appeared over a year ago, or Hybris has also been a cause for concern throughout the year.

Panda Software reminds all webmasters that Panda ActiveScan is available free to all those who want to include it on their website. Administrators can request the application from activescan@pandasoftware.com, indicating their country of origin in the message.

About Panda Software
Panda Software (http://www.pandasoftware.com) is a leading international developer of computer security software, specializing in antivirus solutions for large networks. Their 100% in-house, cutting-edge technology has received awards and quality certifications from the most widely respected IT security institutions. Their commitment to client service and the concept of the protection of computer systems as a 24h-365d Insurance Policy rather than merely a software product have revolutionized the computer security industry. The quality of Panda Softwares products has been endorsed by the major industry watchdogs including: Virus Bulletin, ICSA Labs and Checkmark.