DDOS attack or denial of service attacks is a mode of network disruption in which computer specialists with malevolent intention try to prevent legit users from accessing network resources. Recent DDOS attacks on the users of wikileaks service have brought back the dark memories of the era when these were too commonplace.
Nowadays network administrators are well prepared for network outages and usually mitigate such attacks even before they happen. The rule is to stop all services that are vulnerable to DDOS attacks.
What malevolent computer experts do is make repeated requests to servers for some services,, until the server gives up crashes. This causes major disruptions in the functions of the enterprise or an organization under attack.
These attacks can be very severe sometimes, requiring physical hardware replacements at times. Attackers replace softwares that are vulnerable as well as vital to the normal functioning of the computer system, with damaged or corrupt softwares. Some security experts call these attacks as ‘cyber-terrorism’.
There are several well-known DDOS attacks. One of them is the SQL Slammer virus. This caused an extensive denial of service to as many as 75000 users under 10 minutes. This worm used a vulnerable SQL script on the Microsoft SQL servers worldwide. One specialty of this virus was that it was too small and often ignored, when legit traffic was denied access, the SQL Slammer virus could get through quite easily.
Normal network outages or better known as downtimes have become a thing of the past now. Thanks to the expertise of the network administrators, these are avoided using better network designs and extensive and redundant backups. However, the risk still lingers with computer super powers vying for superior foothold and even trying to cause disruption of emergency services and telecommunications services across the globe.