1. Nmap –The Network Mapper :
Nmap is one of the most widely used open source network mapping utility which scans & detects for ports, Operating systems, its services & used to manage networks. Nmap is available for windows & Linux also but it was basically designed for a linux/Unix box, which works best with it also.
2. John The Ripper Password Cracker
John the Ripper is a fastest password cracker, Now available for many distros of Unix, DOS, Win32, BeOS, and OpenVMS. Its primary purpose is to detect weak Unix passwords. Besides several crypt(3) password hash types most commonly found on various Unix flavors, supported out of the box are Kerberos AFS and Windows NT/2000/XP/2003 LM hashes, plus several more with contributed patches. It is also well known as JTR, the most deadliest cracker of all time.
3. Nessus Remote Security Scanner
Nessus is basically a vulnerability scanner used by most of the well known organizations of the world for making their security audits. Nessus were open source in past, but now its a closed source one but a free software, which scans for thousands of general & critical vulnerability problems in any network.
4. Wireshark – The Sniffer
It was formerly knows as Eathereal. It is network protocol analyzer, or sniffer, that lets you capture and interactively browse the contents of network frames. Its open sources’ness gives it to grow from all dimensions & it gives more than a quality network analyzers that are present in the market.
It have a GUI works great with both Linux & Windows.
Eraser is an advanced security tool (for Windows). We can completely remove sensitive data from your hard drive by overwriting it several times which is done with carefully selected patterns. Eraser is Free software and its source code is released under GNU General Public License as it is a open source one. Works with all versions of windows as -> Windows 95, 98, ME, NT, 2000, XP and DOS. Its great tool for hiding secret things & mainly deleting it.
6. LCP – Windows Password Cracker
LCP is one of the well known free software for cracking windows passwords in many versions like Windows NT/2000/XP/2003. Accounts information import, Passwords recovery, Brute force session distribution, Hashes computing can be easily done by LCP. It is similar to LOphtcrack.
It have various modes like bruteforce, dictionary attack & hybrid attack.
7. Cain & Able Passwords Cracker
Its another password cracker for windows based system. P It collects passwords by sniffing the network, cracking encrypted passwords using Dictionary, Brute-Force and Cryptanalysis attacks, recording VoIP conversations, decoding scrambled passwords, uncovering cached passwords, revealing password boxes,and analyzing routing protocols.
Interesting part is it sniffs itself, we don’t have to search for password files of any kind.
8.SuperScan- Port Scanner
Superscan is great TCP/IP port scanner which is widely used for detecting the open ports or live hosts in given IP ranges. It have a GUI & made for windows & easy to use, don’t miss it.
9. Nikto – CGI Scanner
Nikto is a great CGI scanner, which is an Open Source (GPL) web server scanner which performs comprehensive tests against web servers for multiple items. Which includes 3200 potentially dangerous files/CGIs, versions on over 625 servers, and version specific problems on over 230 servers.
Passive OS fingerprinting tool used widely for scanning operating system and it can scan for any operating system.
P0f can identify the operating system on:
– SYN Mode
– SYN+ACK mode,
– RST+ mode,
– machines whose communications you can observe.
It listens to any communication for detecting OS