A computer worm shut down computer systems running the Windows 2000 operating system across the United States on Tuesday, hitting computers at CNN, ABC and The New York Times.
Around 5 p.m. computers began crashing at CNN facilities in New York and Atlanta. ABC said its problems began in New York about 1:30 p.m.
The Caterpillar Co. in Peoria, Illinois also was reportedly affected.
David Perry of Trend Micro said that the attack seems to have been triggered by a new worm, called worm--rbot.ebq. He said the symptoms -- computers repeatedly shutting down and rebooting -- was consistent with that virus.
Johannes Ullrich, director of the Sans Institute, a network security firm in Jacksonville, Florida, said the outage also may have been caused by the Zotob worm, which was released last weekend.
"It will connect to a control server to ask for instructions. It scans network neighborhoods and tries to infect them, as well," Ullrich said.
Several versions of the worm have been released, some as late as Tuesday, he said.