Top Ten Viruses Reported To Sophos In September 2001

This is the latest in a series of monthly charts counting down the ten most frequently occurring viruses as compiled by Sophos, a world leader in corporate anti-virus protection.

For September 2001, the chart is as follows, with the most frequently occurring virus at number one:

1. W32/Nimda-A (Nimda) 71.1%

2. W32/Sircam-A (Sircam) 11.4%

3. W32/Magistr-A (Magistr) 3.6%

4. W32/Magistr-B (Magistr variant) 3%

5. W32/Hybris-B (Hybris variant) 1.5%

6. W32/Apology-B (Apology variant) 0.7%

7= VBS/Kakworm (Kakworm) 0.68%

7= W32/Flcss (FunLove) 0.68%

9. W32/Bymer-A (Bymer) 0.5%

10. W32/Badtrans-A (Badtrans) 0.44%

Others 6.4%

“Nimda attacks from every angle. It uses a multi-pronged method to exploit a number of known weaknesses,” said Peter Cooper, UK support manager at Sophos Anti-Virus. “Despite the high profile warnings, it is continuing to infect people who have failed to update their virus protection.”

“Ensuring your operating system is fully patched and updated is as important as up-to-date anti-virus software,” continued Cooper. “Had the affected machines been patched up prior to infection, the path and magnitude of Nimda would have been very different.”

890 new viruses were discovered and protected against by Sophos Anti-Virus during September 2001.

The total number of viruses Sophos now detects and protects against is 68111.

Because of the massive amount of people affected by Nimda, Sophos is offering a free detection and disinfection kit. To receive this kit simply send an email to:

For more information about Nimda visit:

Graphics of the above Top Ten chart are available at:

For more information about safe computing visit:

Compiled by Sophos’s technical support team, the top ten chart is collated from submissions to Sophos’s 24 hour, 365 days a year technical support service.

About Sophos

Sophos is one of the world’s largest specialist developers of anti-virus software. The products are sold and supported through a global network of subsidiaries and partners in more than 120 countries. Sophos Anti-Virus is widely used by large corporations, banks and governments.

For further information, please visit

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