Spoofing

To spoof is to impersonate a user or process in an unauthorized way. At its simplest, spoofing can mean typing in a different user's credentials. A malicious uses might also change the contents of a cookie to pretend that he or she is a different user or that the cookie comes from a different server.

In general, you can help prevent spoofing by using stringent authentication. Any time someone requests access to non-public information, be sure they are who they say they are. You can also help defend against spoofing by keeping credential information safe. For example, do not keep a password or other sensitive information in a cookie, where a malicious user can easily find or modify it.