A packet sniffer is

• A. a prepared application that takes advantage of a known weakness.
• B. a tool used to quickly check computers on a network for known weaknesses.
• C. an application that captures TCP/IP data packets, which can maliciously be used to capture passwords and other data while it is in transit either within the computer or over the network.
• D. a situation in which one person or program successfully masquerades as another by falsifying data and thereby gaining illegitimate access.