GNU/Linux related ...
Linux Arab Community is the main support site for GNU/Linux for the Arabs Community.
Redhat Is the Open Source Leader, and is the world's most trusted provider of Linux and open source technology.
Ubuntu is a community developed, Linux-based operating system that is perfect for laptops, desktops and servers. It contains all the applications you need - a web browser, presentation, document and spreadsheet software, instant messaging and much more.
CentOS is a freely-available operating system that is based on Red Hat Enterprise Linux. This rebuild project strives to be 100% binary compatible with the upstream product and, within its mainline and updates, not to vary from that goal. Additional software archives hold later versions of such packages, along with other Free and Open Source Software RPM-based packages. CentOS stands for Community ENTerprise Operating System.
iptables is a user space application program that allows a system administrator to configure the tables provided by Xtables (which in turn uses Netfilter) and the chains and rules it stores.
Penetration Testing & Security related ...
Open Source Security Testing Methodology Manual (OSSTMM) is a peer-reviewed methodology for performing security tests and metrics. The OSSTMM test cases are divided into five channels (sections) which collectively test: information and data controls, personnel security awareness levels, fraud and social engineering control levels, computer and telecommunications networks, wireless devices, mobile devices, physical security access controls, security processes, and physical locations such as buildings, perimeters, and military bases.
Open Web Application Security Project (OWASP) is an open-source application security project. The OWASP community includes corporations, educational organizations, and individuals from around the world. This community works to create freely-available articles, methodologies, documentation, tools, and technologies. The OWASP Foundation is a 501(c)(3) charitable organization that supports and manages OWASP projects and infrastructure.
Technical Guide to Information Security Testing and Assessment, September 2008
BackTrack is the most top rated linux live distribution focused on penetration testing. With no installation whatsoever, the analysis platform is started directly from the CD-Rom and is fully accessible within minutes.
Metasploit Project is a computer security project which provides information about security vulnerabilities and aids in penetration testing and IDS signature development. Its most well-known sub-project is the Metasploit Framework, a tool for developing and executing exploit code against a remote target machine. Other important sub-projects include the Opcode Database, shellcode archive, and security research.
Nessus is a proprietary comprehensive vulnerability scanning software. It is free of charge for personal use in a non-enterprise environment. Its goal is to detect potential vulnerabilities on the tested systems.
Wire Shark is a free packet sniffer computer application. It is used for network troubleshooting, analysis, software and communications protocol development, and education.
Nmap is a security scanner originally written by Gordon Lyon (also known by his pseudonym Fyodor Vaskovich). It may be used to discover computers and services on a computer network, thus creating a "map" of the network. Just like many simple port scanners, Nmap is capable of discovering passive services on a network despite the fact that such services aren't advertising themselves with a service discovery protocol.
SNORT is a free and open source network intrusion prevention system (NIPS) and network intrusion detection system (NIDS) capable of performing packet logging and real-time traffic analysis on IP networks. Snort was written by Martin Roesch and is now developed by Sourcefire, of which Roesch is the founder and CTO. Integrated enterprise versions with purpose built hardware and commercial support services are sold by Sourcefire.
Netcat: the network swiss army knife is a computer networking utility for reading from and writing to network connections on either TCP or UDP. It is the Swiss-army knife for TCP/IP.
HPing3 is a free packet generator and analyzer for the TCP/IP protocol distributed by Salvatore Sanfilippo (also known as Antirez). Hping is one of the de facto tools for security auditing and testing of firewalls and networks, and was used to exploit the idle scan scanning technique (also invented by the hping author), and now implemented in the Nmap Security Scanner.
Ettercap is a 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. Many sniffing modes were implemented to give you a powerful and complete sniffing suite.
THC Hydra a software project developed by a German organization called "The Hacker's Choice" (THC) that uses a dictionary attack to test for weak or simple passwords on one or many remote hosts running a variety of different services. It was designed as a proof-of-concept utility to demonstrate the ease of cracking poorly chosen passwords.
Secure Shell (SSH) is a network protocol that allows data to be exchanged using a secure channel between two networked devices. Used primarily on Linux and Unix based systems to access shell accounts, SSH was designed as a replacement for TELNET and other insecure remote shells, which send information, notably passwords, in plaintext, leaving them open for interception. The encryption used by SSH provides confidentiality and integrity of data over an insecure network, such as the Internet.
Port Knocking is a method of externally opening ports on a firewall by generating a connection attempt on a set of prespecified closed ports. Once a correct sequence of connection attempts is received, the firewall rules are dynamically modified to allow the host which sent the connection attempts to connect over specific port(s).
