Sex sells and the new internet worm (Nyxem-E) nick-named the "Kama  Sutra worm" because it spreads under the guise of pornographic content,  has leap-frogged lesser viruses reaching top-spot on world virus  charts. 

Nyxem-E aka Kama Sutra is a mass-mailing worm which attempts to disable  security-related and file-sharing software and destroys files of  certain types. When run on a Windows PC, the worm copies itself to  shared network locations, and sends itself to e-mail addresses found on  the target computer. Nyxem-E, according to F-Secure, is programmed to  disable anti-virus and firewall software, and delete certain files  including Office documents, on the third day of every month. 

The Kama Sutra worm arrives as an e-mail attachment, with different  subject lines including "School girl fantasies gone bad," "The Best  Videoclip Ever," "A Great Video," "give me a kiss," "Fwd: Photo," "Fw:  Sexy," "You Must View This Videoclip!" "Miss Lebanon 2006," etc. The text differs; it may include references to the Kama Sutra - the ancient 
Sanskrit book on sex and related matters. 

F-Secure has reported a steady stream of Nyxem worms from all over the  world, and has said that at last call the worm showed 510,000 infected  systems. 

Graham Cluley, senior technology consultant, Sophos, said that the Kama  Sutra worm uses a dated technique to entice users by promising  pornography, and that the worm lacks the sophistication of recent  Trojan horse-style viruses. 

Security experts have advised users to keep their anti-virus software 
up-to-date, and be wary whilst opening e-mail attachments. 

Lot of people have lost data due to virus.

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As D-Day for the 'Kama Sutra' worm nears, security firm Sophos is  warning users not to panic over the threat posed by it. 

The W32/Nyxem-D worm, which can pose as pictures of the Kama Sutra, has  a destructive payload, which triggers half an hour after a computer is  booted on the third day of any month, destroying DOC, XLS, MDB, MDE,  PPT, PPS, ZIP, RAR, PDF, PSD and DMP files by replacing their contents  with the phrase: 

DATA Error [47 0F 94 93 F4 K5] 

Nyxem-D worm is also known as Blackworm, Email-Worm.Win32.VB.bi,  Win32/Mywife.e or W32.Blackmal.E@mm. "When you panic, you make  mistakes," said Graham Cluley, senior technology consultant for Sophos.  "Sit down, have a cup of tea, and work out if you have done everything  you should have done to ensure your computer isn't at risk from the  Nyxem worm, and indeed any of the other 120,000 pieces of malware in  existence." 

The W32/Nyxem-D Windows worm does not infect Macintosh computers and  experts believe that home users may be at more risk than businesses because typically they take security issues less seriously. 

"Most businesses have been successfully protecting against this worm  for a couple of weeks," said Cluley. "Home users who have not been  updating their software may be at risk if they are in the habit of  opening unsolicited attachments in emails with dodgy sounding subject  lines. Even if they are infected, and do nothing, and the worm  demolishes their data on Friday, they should be able to recover if they 
have a recent backup. Anyone who suffers from this worm's payload  simply hasn't been practicing safe computing." 

Sophos warns that focusing too much on Nyxem's threat on Friday 3  February may leave people unaware of other malware risks. 

"The damage caused by W32/Nyxem-D has stirred up the public interest 
because it sounds really terrible - but in many ways, it is the less  visible malicious payloads delivered by other malware which can be far  worse," said Cluley. "You may be able to recover the files deleted by  Nyxem by going to backup or retyping the content. But you can never get  back files which a hacker stole from your PC using a backdoor Trojan. 
You can never untype keystrokes which were captured by a keylogger. You  can never unsend the thousands of emails spammed out if your computer  is a zombie." 

"Bottom line - if you're worried about Nyxem-D now is the time to look  for it, but maybe if you're worried about that you also have reason to 
be worried about all the other malware out there," said Cluley. "In  January we saw 2,312 brand new pieces of malware, that's over 500 every  single week." 

Sophos suggests that computer users who are concerned that they may be  at risk ensure that their anti-virus software is properly installed and  up-to-date, and that unsolicited email attachments are not opened.  Additionally, PC users should ensure that they have patched their  computer against the latest Windows security vulnerabilities, and that  a client firewall is installed. Backups of valuable data should be  routine both inside businesses and at home.