It may be this century's most pertinent proverb: "Beware of unknown attachments!" More than 500,000 PCs are thought to have been infected with an e-mail worm, dubbed "the Kama Sutra," programmed to obliterate all Microsoft Word, Excel, Access, and PowerPoint documents as well as Adobe Acrobat and Photoshop files. The worm chows down the third day of every month, starting this Friday. Employing classic social-engineering tactics to spread, victims receive an e-mail enticing them to click on attachments labeled "crazy illegal sex" or "hot movie" unbelievable as it may seem, there are still people who can't resist an attachment promising porn. After download, the worm is unleashed and the e-mail carrying the virus is forwarded to every address on your computer. The worm can also infiltrate your computer through a network, bypassing any blank administrator passwords, making it particularly deadly to small businesses. Finnish antivirus vendor F-Secure has issued a free disinfection tool that may help many save their files. What's different about this worm? Most viruses intend to procure your credit card information, but this one has no clear profit motive it's just about destruction. The Kama Sutra may have saved many a stale marriage, but as of Friday, its new mission is to destroy.