Network Sniffer Attacks

摘要

One of the author's clients dismissed the possibility of a network sniffer attack. He said, #x201C;Network sniffers are not a concern. They cost $20,000 or more, so hackers cannot afford one.#x201D; He was wrong because there are many network sniffers that cost much less than $20,000. For example, there are free or almost free sniffers for the IBM PC with MS-DOS. Plus there are many sniff- ers for Windows 95, Windows NT, UNIX, and even hand-held computers. These sniffers are powerful and can capture user IDs and passwords or possibly confidential data from a network.