Yahoo was not the only site to show how vulnerable the Internet is when it comes to malicious attacks - other big names also fell victim this week.
Following the co-ordinated, distributed denial-of-service attack on Yahoo on Monday, Amazon.com, eBay.com and Buy.com also had their services temporarily crippled.
Amazon.com's service was dramatically slowed down, while the other sites were intermittently unavailable.
The attack on Buy.com attack coincided with the company's public offering of stock which saw shares close at $25.125 each. Buy.com said it had expected a dramatic increase in traffic due to its IPO, but said traffic levels had suffered.
The companies are still not sure whether the attacks are related, although due to their similarity, security experts believe it is unlikely they are coincidental.
In all attacks a technique known as distributed denial of service was used. In effect, this hijacks computers around the Internet and instructs them to jam a site with 'fake' or meaningless data. As the site's servers desperately try to cope with all the 'fake' data, it slows down, and in some cases stops authentic customers getting on the site.
Although these distributed denials of services are vandalism that can cost sites many thousands of dollars in advertising, they do not allow access to sensitive secure data such as consumer's credit card details.
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