10 – Security Issues

This chapter provides an overview of security threats and security fixes. Malware is any software that may do something nasty to a network. There are several types of malware, each of which propagates differently and has a different goal: virus, worm, Trojan horse, and spyware. A denial-of-service (DoS) attack attempts to prevent legitimate users from accessing a computing resource. A distributed DoS attack uses multiple source computers to disrupt its victims. The simplest type of virus detection software is host-based. Its job is to scan a single computer and look for any malware that is stored on the host's hard disk, either as separate files or embedded in other files. Symantec's antivirus is intended to protect an entire network. It provides centralized management of software that scans servers as well as end-user systems. A firewall is a piece of software— running on a computer, a router, or a stand-alone appliance—that prevents unwanted packets from gaining access to the network.