This section describes the types of the network attacks.

Network attacks can be divided into the following three types:

• Denial of service attacks

  • Denial of Service (DoS) attacks are to attack a system by sending a large number of data packets. As a result, the system cannot receive requests from valid users, or the host is suspended and cannot work normally.

    The main DoS attacks include: SYN Flood and Fraggle. The DoS attack differs from other types of attacks. For the DoS attack, attackers prevent valid users from accessing resources or routers. In other types of attacks, attackers search for ingresses of intranets.

  • Distributed Denial of Service (DDOS) attacks are one type of DoS attacks. For the DDOS attacks, attackers attack a host by using tens or hundreds of computers under their control, so that the system of the host cannot accept normal requests of valid users or the host is suspended and cannot work normally.

• Scanning and snooping attacks

  Scanning and snooping attacks are to point out a potential target by identifying an existing system on the network by means of ping scanning (including ICMP and TCP). Through TCP and UDP port scanning, attackers detect the running system and the monitoring services and then obtain the information about the service types and the potential security defects of the system so as to prepare for further intrusion.

• Malformed packet attacks

  A malformed packet attacks are to send malformed IP packets to the destination system so that the system crashes when it processes such IP packets. Malformed packet attacks include Ping of Death and Teardrop