On this day in economic and financial history ...

Savvy Internet users know better than to click on strange files, but in 1988, the idea of an Internet virus  had yet to take hold -- perhaps because the idea of the Internet hadn't spread far beyond the halls of academia. The highly public discovery and eradication of the Morris worm bore a few similarities to the classic 1980s movie WarGames, including worm creator Robert T. Morris' vague resemblance to preternaturally youthful WarGames star Matthew Broderick.

On Nov. 4, 1988, some of the country's leading computer scientists finally unmasked Morris, at the time described as a "brilliant" Cornell graduate student and the son of one of the government's top network security specialists. The Morris worm had by this point infected nearly all of the nodes on the 300-member ARPANET, reserved for research by major public and private institutions. The successful scrubbing of the Morris worm from ARPANET helped boost the largely unprotected network's security, as Defense Department officials crowed that modifications had been made to prevent a similar "act of sabotage."

Today, the Internet is teeming with all forms of unsavory malware. A study released in mid-2012 estimated that computer viruses cost the world's businesses a staggering $1.5 trillion per year in lost productivity. U.S. businesses shoulder a $266 billion annual cost for dealing with virus-wrought havoc. 

American businesses have a lot of options for protection, though. Two Dow Jones Industrial Average (DJINDICES:^DJI) components are major antivirus purveyors -- Microsoft (NASDAQ:MSFT) is the leading provider of antivirus software in North America, with a 27% total market share, and Intel's (NASDAQ:INTC) McAfee, which controls more than 5%. Symantec (NASDAQ:SYMC) has one of the largest slices of the pie relative to its size, controlling 21% of the North American antivirus market. Dow component Cisco (NASDAQ:CSCO) also works to keep its customers safe with higher-end security solutions focused on various layers of email defense and screening .

Fool contributor Alex Planes holds no financial position in any company mentioned here. Add him on Google+ or follow him on Twitter, @TMFBiggles, for more news and insights.

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