SecTools

KisMAC : A A GUI passive wireless stumbler for Mac OS X
This popular stumbler for Mac OS X offers many of the features of its namesake Kismet, though the codebase is entirely different. Unlike console-based Kismet, KisMAC offers a pretty GUI and was around before Kismet was ported to OS X. It also offers mapping, […]

EtherApe : EtherApe is a graphical network monitor for Unix modeled after etherman
Featuring link layer, IP and TCP modes, EtherApe displays network activity graphically with a color coded protocols display. Hosts and links change in size with traffic. It supports Ethernet, FDDI, Token Ring, ISDN, PPP and SLIP devices. It can filter traffic to be […]

Ngrep : Convenient packet matching & display
ngrep strives to provide most of GNU grep’s common features, applying them to the network layer. ngrep is a pcap-aware tool that will allow you to specify extended regular or hexadecimal expressions to match against data payloads of packets. It currently recognizes TCP, UDP and ICMP across Ethernet, PPP, […]

Ntop : A network traffic usage monitor
Ntop shows network usage in a way similar to what top does for processes. In interactive mode, it displays the network status on the user’s terminal. In Web mode, it acts as a Web server, creating an HTML dump of the network status. It sports a NetFlow/sFlow emitter/collector, an […]

NetStumbler : Free Windows 802.11 Sniffer
Netstumbler is the best known Windows tool for finding open wireless access points (”wardriving”). They also distribute a WinCE version for PDAs and such named Ministumbler. The tool is currently free but Windows-only and no source code is provided. It uses a more active approach to finding WAPs than passive […]

Dsniff : A suite of powerful network auditing and penetration-testing tools
This popular and well-engineered suite by Dug Song includes many tools. dsniff, filesnarf, mailsnarf, msgsnarf, urlsnarf, and webspy passively monitor a network for interesting data (passwords, e-mail, files, etc.). arpspoof, dnsspoof, and macof facilitate the interception of network traffic normally unavailable to an attacker (e.g, […]

Ettercap : In case you still thought switched LANs provide much extra security
Ettercap is a terminal-based network sniffer/interceptor/logger for ethernet LANs. It supports active and passive dissection of many protocols (even ciphered ones, like ssh and https). Data injection in an established connection and filtering on the fly is also possible, keeping the connection synchronized. […]

Cain and Abel : The top password recovery tool for Windows
UNIX users often smugly assert that the best free security tools support their platform first, and Windows ports are often an afterthought. They are usually right, but Cain & Abel is a glaring exception. This Windows-only password recovery tool handles an enormous variety of tasks. […]

Tcpdump : The classic sniffer for network monitoring and data acquisition
Tcpdump is the IP sniffer we all used before Ethereal (Wireshark) came on the scene, and many of us continue to use it frequently. It may not have the bells and whistles (such as a pretty GUI or parsing logic for hundreds of application protocols) […]

Kismet : A powerful wireless sniffer
Kismet is an console (ncurses) based 802.11 layer2 wireless network detector, sniffer, and intrusion detection system. It identifies networks by passively sniffing (as opposed to more active tools such as NetStumbler), and can even decloak hidden (non-beaconing) networks if they are in use. It can automatically detect network IP blocks […]

Wireshark : Sniffing the glue that holds the Internet together
Wireshark (known as Ethereal until a trademark dispute in Summer 2006) is a fantastic open source network protocol analyzer for Unix and Windows. It allows you to examine data from a live network or from a capture file on disk. You can interactively browse the capture […]