The glossary below contains many of the terms you will find in common use throughout the Symantec Security Response website. Please refer to this list to find definitions of terms and answers to other Internet security-related questions.


A type of attack where an intruder takes control of an existing communication session between a server and a legitimate user who has connected and authenticated with the server. The intruder can monitor the session passively recording the transfer of sensitive information such as passwords and code. Another type of hijacking involves an active attack done by forcing the user offline (with a Denial of Service attack) and taking over the session. The intruder begins acting like the user, executing commands, and sending information to the server.