1) Nessus (vulnerability scanners)
What Is It?:
Nessus is a freely available, open-source vulnerability scanner.
Why Use Nessus?:
The power and performance of Nessus, combined with the price- FREE- make it a compelling choice for a vulnerability scanner
2) Wireshark (packet sniffers)
What Is Wireshark?:
In short, a network protocol analyzer, otherwise known as a "packet sniffer", captures and decodes packets of information from a network. Wireshark can capture live network traffic or read data from a file and translate the data to be presented in a format the user can understand.
3) Snort (IDS-intrusion detection system)
Snort® is an open source network intrusion prevention and detection system (IDS/IPS) developed by Sourcefire. Combining the benefits of signature, protocol, and anomaly-based inspection, Snort is the most widely deployed IDS/IPS technology worldwide. With millions of downloads and nearly 400,000 registered users, Snort has become the de facto standard for IPS.
4) Metasploit Framework
Metasploit software helps security and IT professionals identify security issues, verify vulnerability mitigations, and manage expert-driven security assessments, providing true security risk intelligence. Capabilities include smart exploitation, password auditing, web application scanning, and social engineering. Teams can collaborate in Metasploit and present their findings in consolidated reports.
5) Cain and Abel
(password crackers or packet sniffers)
Cain & Abel is a password recovery tool for Microsoft Operating Systems. It allows easy recovery of various kind of passwords by sniffing the network, cracking encrypted passwords using Dictionary, Brute-Force and Cryptanalysis attacks, recording VoIP conversations, decoding scrambled passwords, recovering wireless network keys, revealing password boxes, uncovering cached passwords and analyzing routing protocols.