Network Security, Firewalls, and VPNs, 3rd Edition

Hijack and Replay Attacks

A hijack attack occurs when a hacker uses a network sniffer to watch a communications session to learn its parameters. The hacker then disconnects one of the session’s hosts, impersonates the offline system, and begins to inject crafted packets into the communication stream. If successful, the hacker takes over the session of the offline host, while the other host is unaware of the switch.

Replay attacks are also known as playback attacks. A replay attack occurs when a hacker uses a network sniffer to capture network traffic, and then retransmits that traffic back on to the network at a later time. The goal of a replay attack is to gain interactive or session access to a system.

The traffic captured and retransmitted ...