Authorities in South Korea issued a security alert today against a fast-spreading computer "worm" that prompted major delays in global web traffic and crippled South Korea's entire on-line service.
South Korea's Information and Communication Ministry blamed the worm for scrambling the country's high-speed broadband and mobile Internet services yesterday.
The ministry issued urgent public guidelines advising all Internet users and service firms using Windows NT, Windows 2000 and Windows XP to download patches, or fixes, available on Microsoft Corp's Web site.
Called "Sapphire" or "SQL Slammer", the worm carries a self-regenerating mechanism that enables it to multiply quickly across the Web. It triggers a huge volume of transmissions flowing into systems.
The worm rapidly spread across the world over the weekend, infesting networks and slowing global Internet traffic. It targets a previously identified weakness in Microsoft's popular database software "SQL Server 2000".
It was the largest attack on the Internet since the Nimda virus struck on the one-week anniversary of the September 11th, 2001, terrorist attacks.
The Sapphire affected nearly 250,000 computers worldwide by yesterday evening, said Mr Vincent Gulloto, vice president of MacAfee Avert Labs and leader of Network Associates' Antivirus Response Team in the US.
US security experts feared it was just a prelude to a bigger cyber-assault.
In Japan, Trend Micro, a major virus fighter, said that clients in China, Taiwan, South Korea and the United States have reported major networking problems.
Unlike an e-mail virus, the worm does not erase data but quickly copies itself and infects computer servers that run on Microsoft Windows 2000 SQL software.
Although Ireland.comwasn't infected by the worm, a number of internet service providers did encounter problems which resulted in users having difficulty accessing Ireland.comontent.