Viruses are spread by several methods, including running executable code, sharing disks or USB drives, opening email attachments, and viewing infected or malicious web pages. Viruses can attach to other executables or replace them in order to spread or execute. Viruses require user intervention to run.
Viruses, worms, and Trojan programs are a major security threat. They can damage files, enable attackers to control computers, and prevent applications from functioning correctly. When creating a network defense perimeter, you need to consider guarding against all three. Firewalls and Intrusion Detection Systems do not block malicious code on their own; you need to install anti-malware software or proxy servers that can be configured to filter out malicious code and delete it before it causes harm.
User Awareness and Information Security Training: Empowering the user is always the first line of defense. Diligent and educated users will automatically be wary of virus delivery methods such as SPAM or Phishing emails, unsolicited email attachments, and fraudulent internet pages advertising free anti-virus scans, and more.
Anti-Virus / Anti-Malware End-Point Protection: There are many free anti-virus solutions for home users, for Windows, Linux and
Macintosh computers. Regardless of the operating system you use, anti-virus is a
must-have. This protection provides a second layer of defense, and will intervene
if the computer user (or some background program process) attempts to execute or interact
with a virus. Furthermore, anti-virus solutions typically quarantine the malicious
program, placing it in an isolated location which can allow for further review by
a technician or information security practitioner.