Top Ten Viruses Reported To Sophos In July 2002

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

For July 2002, the virus chart is as follows, with the most frequently occurring virus at number one:

1. W32/Klez-H (Klez variant) 17.7%
2. W32/Frethem-Fam (Frethem) 17.0%
3. W32/Yaha-E (Yaha variant) 16.8%
4. W32/Badtrans-B (Badtrans variant) 5.8%
5. W32/Elkern-C (Elkern variant) 3.7%
6. W32/Magistr-B (Magistr variant) 2.5%
7. W32/Hybris-B (Hybris variant) 1.9%
8. W32/Klez-E (Klez variant) 1.7%
9. W32/Nimda-A (Nimda variant) 1.5%
10. W32/Magistr-A (Magistr variant) 1.3%
Others: 30.1%

“While Klez tops the virus chart again this month, more recent discoveries Frethem and Yaha are close on its heels,” said Graham Cluley, senior technology consultant at Sophos Anti-Virus. “Yaha came to prominence as a politically motivated virus, launching a rudimentary denial of service attack on the Pakistan Government’s website and encouraging Indian hackers and virus writers to join forces and attack Pakistan.”

“Arriving in an email with the subject ‘Re: Your password’, Frethem relies on a simple psychological trick to entice users to open the email. The worm is contained in an attached EXE file. As ever, blocking unwanted filetypes at the gateway would deal with these viruses.”

The top ten hoaxes reported to Sophos during July 2002 are as follows:


Hotmail hoax 7.3%
A virtual card for you 6.3%
Bill Gates fortune 5.3%
Frog in a blender/ fish in a bowl 4.8%
Budweiser frogs screensaver 4.6%
Nigerian letter 3.8%
ATM theft 3.4%
JS/Exploit 2.9%
Meninas de Playboy 1.8%
Others: 46.6%

“JDBGMGR has dominated the hoax chart since its discovery in May,” continued Cluley. “The prevalence of ‘A Virtual Card for you’ and ‘Budweiser frogs screensaver’ several years after they originated highlights both the severity of hoaxes and how far we still have to go in educating users in safe computing practices. Unlike viral code, hoaxes are not detected or disabled by anti-virus software, so can continue to clog up email bandwidth longer than many true viruses. To prevent this, computer users should refrain from forwarding virus warnings to their friends and colleagues.”

810 new viruses were discovered and protected against by Sophos during July 2002. The total number of viruses Sophos now detects and protects against is 75281.

For more information about Klez, please visit:

Graphics of the above Top Ten chart are available at:

For more information about safe computing, including anti-hoax policies, please visit:

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