Packet Sniffing - By Aarti Dhone

Introduction

Packet Sniffer Definition:

A packet sniffer is a wire-tap device that plugs into computer networks and eavesdrops on the network traffic.

What are the components of a packet sniffer?

1. Hardware : standard network adapters .2. Capture Filter : This is the most important

part . It captures the network traffic from the wire, filters it for the particular traffic you want, then stores the data in a buffer.

3. Buffers : used to store the frames captured by the Capture Filter .

What are the components of a packet sniffer?

4. Real-time analyzer: a module in the packet sniffer program used for traffic analysis and to shift the traffic for intrusion detection.

5. Decoder : "Protocol Analysis" .

How does a Sniffer Work?

Sniffers also work differently depending on the type of network they are in.

1. Shared Ethernet2. Switched Ethernet

How can I detect a packet sniffer?

Ping method ARP method DNS method

Packet Sniffer Mitigation

The following techniques and tools can be used to mitigate sniffers: Authentication—Using strong authentication, such as one-time

passwords, is a first option for defense against packet sniffers. Switched infrastructure—Deploy a switched infrastructure to counter

the use of packet sniffers in your environment. Antisniffer tools—Use these tools to employ software and hardware

designed to detect the use of sniffers on a network. Cryptography—The most effective method for countering packet

sniffers does not prevent or detect packet sniffers, but rather renders them irrelevant.

Host A Host BRouter A Router B

Top 11 Packet Sniffers Wireshark Kismet Tcpdump Cain and Abel Ettercap Dsniff NetStumbler Ntop Ngrep EtherApe KisMAC

Working of Cain & Abel

What are sniffers used for?

Detection of clear-text passwords and usernames from the network.

Conversion of data to human readable format so that people can read the traffic.

Performance analysis to discover network bottlenecks.

Network intrusion detection in order to discover hackers.

Referenceshttp://netsecurity.about.com/cs/hackertools/a/aa1

21403.htmhttp://e-articles.info/e/a/title/Packet-Sniffing:-Sniffi

ng-Tools-Detection-Prevention-Methods/http://sectools.org/sniffers.htmlhttp://en.wikipedia.org/wiki/Cain_and_Abel_(softw

are)http://www.authorstream.com/Presentation/chinm

ayzen-79529-packet-sniffers-education-ppt-powerpoint/

http://www.youtube.com/watch?v=O00LENbtiIw

Thank You !

Questions ?