Free and Open-Source Software
Free and Open-Source Software (FOSS) is software that is Free Software and Open-Source Software. There is so much FOSS in the security domain that I believe this warrants its own wiki page.
A
AirCrack-NG - A complete suite of tools to assess WiFi network security
Angry IP Scanner - A port and host scanner for Windows.
B
Burp Suite Community Edition - Web Application testing software
C
Cain and Abel - A freely available Windows password sniffer and cracker
D
E
F
G
H
Hash Suite - A Windows-based high-performance password cracker
I
IPTables - The userspace command line program used to configure the Linux 2.4.x and later packet filtering rulesets
J
John the Ripper - A multi-platform password cracker
K
L
L0phtCrack - An open-source password hash cracker
M
Medusa - The massively speedy, highly parallel, modular login brute-forcing password cracker
N
NCrack - A high-speed, multi-platform network authentication cracking tool
Nikto - A free command-line utility vulnerability scanner
NMap - A network discovery and security auditing port/host scanner
O
ophCrack - An open-source Windows-password cracking program
P
Q
R
S
Snort (Community Ruleset) - A free and open-source network intrusion detection system (NIDS) and intrusion prevention system (IPS)
T
tcpdump - A powerful command-line packet analyzer
THC-Hydra - A GPLed proof-of-concept password cracking tool
U
V
W
Wfuzz - A web application security assessment tool
Wireshark - The world’s foremost, widely-used network protocol analyzer
X
Y
Z
Zed Attack Proxy - The world's most widely used web application scanner
