The first attacks were spotted over the weekend after news outlets such as ABC, CNN, the Associated Press and The New York Times were hit hard and fast and, in some cases, operations were temporarily halted.
An ABC spokesman told reporters that producers had to use electric typewriters Tuesday to prepare copy for the “World News Tonight'' broadcast, and CNN interrupted programming to tell viewers that a worm was causing its system to repeatedly shut down.
The attack comes a week after Redmond, Wash.-based Microsoft Corp. warned of a security hole in the Windows 2000 platform, which some computer security firms believe triggered hackers to immediately exploit the vulnerability before Microsoft was able to offer a patch. By Wednesday, four more variants of the same worm were discovered by F-Secure Corp, bringing the total to 11.
The worm travels through Internet connections rather than through email, Sophos reported.
“Once one of these worms has control over your computer, it can use your PC for sending spam, launching an extortion denial-of-service attack against a website, stealing confidential information or blasting out new versions of malware to other unsuspecting computer users," Sophos’senior technology said in a statement.
An estimated 12,000 computer were hit in San Diego County alone, Reuters reported. The worst of the attacks occurred in the United States, with only a few isolated problems in other countries. So far the worms have caused problems for networked systems, rather than home computer users.
Some theories floating around various security firms suggest that hackers are creating the variants in order to compete with each other, removing previous worms from the infected computer and replacing it with a newer variant.