May 1, known as Labor Day in some countries, has long been a day associated with protests relating to workers' rights.
The agency, in an information system advisory issued Friday, said that it has received information suggesting that computer activists might well take advantage of the planned Global Action Against Capitalism real-world demonstrations to launch cyberattacks. Those most at risk from such attacks would be the perceived bastions of capitalism -- international finance houses and trade agencies, according to NIPC.
DoS attacks effectively disable a company's Web site by bombarding it with a high volume of information requests in a short period of time thus causing the site to crash or grind to a halt.
Earlier this year, the likes of Yahoo, eBay, Amazon.com and ETrade Group all suffered DoS attacks, resulting in estimated damages of over $US1 billion.
In addition to DoS attacks, would-be cyberattackers might also to seek to disrupt a company's online operations by mounting "virtual sit-ins" where the number of requests for a particular Web page are so great that the firm's Web server is completely overwhelmed and unable to process the volume of requests, the agency said.
The U.S. Department of Justice (DOJ) and the Federal Bureau of Investigation (FBI) set up NIPC at FBI headquarters in Washington, D.C., in February 1998.
The NIPC's mandate is to act as the national focal point for both assessing, investigating and dealing with attacks on mission-critical infrastructures, according to information on NIPC's Web site.