CompTIA Security+ Exam Prep

Answer - D - Sniffers monitor network traffic and display it in real time. They are originally designed for network maintenance and troubleshooting, but of late they are used by hackers.

Key Takeaway: Sniffing is the electronic form of eavesdropping on communications that computers transmit across networks. A sniffer asks the NIC to stop ignoring all the traffic headed to other computers and pay attention to them. It places the NIC in a state known as promiscuous mode to perform this action. Passive sniffing is mostly performed when the user is on a hub. Because the user is on a hub, all traffic is sent to all ports. All the attacker must do is start the sniffer and wait for someone on the same collision domain to start sending or receiving data.