One last important aspect regarding security is the maintenance of the system itself. The best example of that is the Code Red computer worm, which exploited a weak point in the Windows web server IIS (at that time it was still called Internet Information Service) and spread really quickly. Naturally, Microsoft carries a lot of the blame for that. The server was susceptible and was installed and updated as the default with many Windows versions. Even worse, the problem had been recognized and repaired; a patch was available for it 18 months before Code Red attacked. There are numerous similar examples. Naturally there are also Zero Day Exploits (malicious code, which exploits a security gap and is published simultaneously with the announcement of the gap), but a lot of adversity could have been prevented, if administrators and end users had taken care of their security updates in time. For instance, Microsoft did not repair one weak point in Windows until...