Hacker attacks against network infrastructures can be easy, because many
networks can be reached from anywhere in the world via the Internet. Here
are some examples of network-infrastructure attacks:
Connecting into a network through a rogue modem attached to a
computer behind a firewall
Exploiting weaknesses in network transport mechanisms, such as TCP/IP
and NetBIOS
Flooding a network with too many requests, creating a denial of service
(DoS) for legitimate requests
Installing a network analyzer on a network and capturing every packet
that travels across it, revealing confidential information in clear text
Piggybacking onto a network through an insecure 802.11b wireless
configuration