Now this is fascinating. What's really going on here? Who is starting these and why? Is it better to just be having cyber war and let the computers fight each other? Or does this lead to real war? An attack on the US economy? Economic battles?
Fresh warning over cyber attack
home pc user
The attack targeted Microsoft database software
Experts are warning that a malicious computer code which disrupted the internet may resume its attacks on Monday.
In South Korea, which was badly affected by the attack, systems engineers are racing to repair internet networks amid fears Monday would bring new outbreaks as businesses switch on their computers for the new working week.
The problem is not completely resolved and we will have to have more of a sense of the importance of security
S Korea's Information Minister
The South Korean Information Minister, Lee Sang-Chul, said he believed the problem was hiding, rather than fully resolved.
Computer experts said the code, known as a worm, had affected nearly a quarter of a million computers worldwide on Saturday.
The attack, which targets internet servers and does not infect home computers, slowed systems for several hours, affecting web browsing and e-mail delivery.
The attack was detected by the FBI shortly after it was launched on Saturday, limiting the damage.
Computer experts said the effect was similar to that of the "Code Red" virus, which brought internet traffic to a halt in the summer of 2001.
Companies need to take applying patches against new security threats seriously
Expert at anti-virus company Sophos
At least five of the internet's 13 major hubs were targeted in Saturday's attack.
Internet surfing in Asia was particularly slow.
In South Korea, the world's most wired country where almost three-quarters of the population have internet access, services shut down nationwide for hours on Saturday.
Users and news media also reported outages or slowdowns in Thailand, Japan, Malaysia, the Philippines and India.
In the US, Bank of America customers were unable to withdraw money from the company's 13,000 ATM machines, while the attack also disabled some trans-Atlantic internet and phone service.
Not a virus
The worm known as SQL ("sequel") Slammer targeted a known weakness in Microsoft's software to shut down powerful server computers around the world and can knock websites off-line.
Unlike viruses, the worm exists only in memory, so it cannot be detected by traditional anti-virus scanners.
The Microsoft website has a fix for the vulnerability, which companies can download.
"Companies need to take applying patches against new security threats seriously," said Graham Cluley, senior technology consultant at the anti-virus company Sophos.
"If you don't, then stopping new worms and viruses is as easy as catching smoke in a butterfly net."