These are Top 20 Hacking Tools, the list is exhaustive, this are a few to name.

Nessus
The “Nessus” Project aims to provide to the internet community a free, powerful, up-to-date and easy to use remote security scanner for Linux, BSD, Solaris, and other flavors of Unix.
Ethereal
Ethereal is a free network protocol analyzer for Unix and Windows. Ethereal has several powerful features, including a rich display filter language and the ability to view the reconstructed stream of a TCP session.
Snort
Snort is an open source network intrusion detection system, capable of performing real-time …

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