Hack I.T.: Security Through Penetration Testing

Chapter 14. Sniffers

Sniffers are programs that passively monitor and capture network traffic. Almost any laptop or PC can be turned into a sniffer by installing sniffer software, much of which is freely available on the Internet. The system running the sniffer should have a network interface card that can be used in promiscuous mode. Promiscuous mode enables the sniffer to view but not respond to network traffic, thereby making the sniffer essentially invisible on the network. Sniffers are very useful tools during penetration testing and network troubleshooting. We commonly use them to capture user names and passwords from FTP and telnet sessions. In addition, sniffers can be used to capture any network traffic that is not encrypted, such as ...