some software applications have default settings that allow other users to access your system unless you reconfigure the settings. Examples include chat programs that let outsiders execute commands on your system or Web browsers that could allow someone to place harmful programs on your computer that run when you click on them.

Unfortunately, intruders are always discovering new vulnerabilities (informally called "holes") to exploit in computer software. The complexity of software makes it increasingly difficult to fully test. When holes are discovered, computer vendors will make patches to fix them. However, it is up to the user to find and install the patches. Most of the incident reports of computer break-ins received at Help Desk USA, Inc. could have been prevented if system administrators and users kept patches up-to-date.