Types of Attacks

Network attacks are usually one of four types, denial of service, or DOS, packet fragment, spoofing, or sniffing. Several mechanisms such as viruses, plug-ins, and malicious code are used to perpetrate these attacks.Denial of Service, or DOS, attacks are intended to prevent organizations from using the system or system services. For example, hackers may flood an organization with e-mails or process requests. The system becomes so bogged down with responding to these requests that it is unable to do anything else. Experienced hackers may orchestrate a distributed denial of service, or DDOS, attack by using other computers to deny service to a targeted network.

Packet fragment attacks occur when an intruder alters packets by removing header information or hiding system commands within multiple packet fragments. Without correct header information, the destination computer is unable to assemble the packets correctly. Unauthorized system commands can be transmitted through a firewall by splitting one command into multiple packet fragments.

Spoofing attacks occur when an intruder is able to impersonate, or spoof, a local system�s identification or a network user�s e-mail address. By spoofing a trusted identity, an intruder can bypass network security features and access, steal, damage, or modify network resources and capabilities.

Sniffing attacks occur when an intruder uses canned scripts or tools to steal unencrypted data such as e-mail. It is a passive form of attack intended to gather information about a network. Once this information is stolen, the network is vulnerable to an attack that is not easily detected.