Klez clings on to virus top spot

Internet worm Klez has clung onto the top spot for the most frequently occurring virus, according to antivirus firm Sophos.

The virus accounted for 17 per cent of all viruses reported in August. It also held the top spot in July.

Klez deletes files on local and network drives and overwrites files with random data, making them impossible to restore.

The reasons for the worm's prolific nature have been put down to an ability to cover its tracks by using a random name from an infected machine's address book as the sender address, as well as using a large selection of subject lines.

Klez was last month crowned the biggest virus of all time, ahead of SirCam, Melissa and I Love You, according to antivirus specialist MessageLabs.

The company found around 20,000 instances of Klez being recorded each day, affecting one in every 300 emails.

According to Sophos, the list for August remains full of older viruses, proving that users are still not heeding warnings to keep antivirus software up-to-date.

Graham Cluley, senior technology consultant at Sophos, said: "Only two viruses in August's top 10 are brand new entries. Instead, the chart is full of old stalwarts such as Klez-H, Badtrans-B, SirCam and Nimda.

"Klez-H, and its nasty bedfellow ElKern-C, have accounted for almost a quarter of enquiries to Sophos' support centre this month, even though protection has been available since February.

"Users getting caught out appear not to have updated their antivirus software in six months. With hundreds of new viruses appearing each month, this lax approach is just asking for a security breach."

Cluley also warned that hoax viruses cause users almost as much trouble despite the fact that they are easy to block.

"Hoaxes continue to cause almost as much confusion as real viruses," he said. "The multi-lingual JDBGMGR hoax, which claimed to be an extremely dangerous virus, has been perplexing computer users ever since it first appeared in May.

"Simple to implement anti-hoax policies can help limit this confusion and will prevent hoaxes from needlessly clogging up email servers and wasting valuable bandwidth."