CertiGuide to Security+  9  Chapter 1:  General Security Concepts (Domain 1.0; 30%)

Naïve Web Applications 1 1.5.1  Viruses

Malicious code is program code specifically written for a malicious purpose (rather than code written for a legitimate purpose, which a cracker figured out how to misuse). For example, you would call a piece of code malicious if it deliberately did something like:

• Delete files on your disk, or reformat your disk, without the user’s knowledge
  
  
• Report the contents of your email address book to a web server collecting email addresses for a spammer
  
  
• Display “Ha ha, you’ve been rooted!” and other such messages on your computer
  
  
• Replace certain system files with other files, causing programs to malfunction
  
  
• Capture your network password and email it to joe@cracker.com

This section discusses some different types of malicious code you may encounter out in the field when administering or managing security for a network. Each type of code discussed below differs mainly in how it gets propagated from one user (or system) to another, and how it gets activated to do its dirty deed(s) once it gets onto a system, rather than in the functionality the destructive program itself provides.

Naïve Web Applications 1 1.5.1  Viruses