Sniffing and spoofing network traffic
You have most likely noticed the motto of Kali Linux, The quieter you are the more you are able to hear. This is the heart of sniffing network traffic. You quietly listen to the network traffic, copying every packet on the wire. Every packet is important or it wouldn't be there. Think about that for a moment with your security hat on. Do you understand why sending passwords in clear text is so bad? Well, protocols like Telnet, FTP, and HTTP send the passwords in clear text, instead of an encrypted hash. Any packet sniffer will catch these passwords, and it doesn't take a genius to launch a search of the packet capture for terms like Password. No need to crack a hash, it's just there. You can impress a manager or a client by just pulling their clear-text password out of thin air. The bad guys use the same technique to break into networks and steal money and secrets.
More than just passwords can be found within your copied packets. Packet sniffers are...