Security concerns are unfortunately very important aspects of modern information technologies. The main reason is widespread use of unsafe operating system architectures, especially at desktops. Security updates patch system vulnerabilities in weekly cycles, preventing the possibility of total system crashes and data losses (just opening an e-mail might trigger exploits of vulnerabilities). Even virtually harmless file formats could infiltrate malicious programs (images or pdf-files), one click on a hyperlink could emit sensitive information or even start harmful software hosted on hijacked servers.

Appropriate anti-virus software should be installed on every desktop computer, in particular following criteria should be examined:

• high detection rates (intelligent heuristics), few "false alarms"

• low CPU/disk burden despite high scan speeds

• updates and fitness for networks

• ability to detect rootkits

Protection against spyware is of highest priority, too, since those spyware programs might access and publish passwords. The attack scenarios var and range up to perfidious software, which pretends to protect against spyware or even encrypts user data for blackmail. Protection programs work like antivirus software and observe changes in system behavior, too, e.g. if autostart entries are set up for a program on the computer.

The question of "firewalls on the desktop" is often discarded with reference to external firewalls. Desktop firewalls, however, are important additional barriers against any unrecognized malicious programs operating in intranets or connecting to internet servers ( "phoning home"). A desktop firewall should recognize manipulations of computer software, too. Products have to be compared and configured carefully, primarily because of time consuming interactions with users and possibilities of circumvention by malware.