Everyone that uses computers will most likely develop a preference for a particular operating system. In my opinion, you should use what works best for you. There are arguments good and bad for any system you might be interested in using. Here, I will explain why crackers choose to use a particular operating system.

Windows Operating Systems

Windows is arguably the most popular operating system available these days. It is easy to use, and is installed on the majority of systems shipped in the world. Windows has been translated to multiple languages and is run by users all over the world. It certainly doesn't appeal to most users as a cracker OS, but it does get used in this arena. In most cases, script kiddie crackers used the Windows operating system. There are many cracking utilities and such written for the Windows environment. These prepackaged apps generally are not powerful enough to penetrate most systems. Most of these utilities are for mail bombing, denial of service, port scanning, and IRC (Internet Relay Chat) user attacks. Windows is of limited use to intelligent attackers, and, therefore, I only reference it briefly.

Linux/NetBSD/FreeBSD

The open source software movement has given the Internet community and computer users everywhere a plethora of robust and reliable operating systems. The most common ones you will hear of or use are Linux, FreeBSD, or NetBSD, which are popular with both the cracking underground and security professionals alike.

Open source operating systems are very popular simply because they are open source. This means that the end user has full access to the source code of the entire operating system. This allows the user to learn and understand how the system works, how to make it secure, and how to exploit its weaknesses on other computers. Another benefit of it being open source is the speed of patch releases. In most cases, the moment a security issue is released relating to an open source operating system, it will typically be fixed and patched within an hour or less of the initial announcement. This allows the end user to maintain every aspect of system security, including the ability to patch the operating system when necessary. Most crackers using open source operating systems, such as Linux, learned security exploitation techniques while securing and maintaining their own systems.

Another benefit of an open source OS is that the cracker has full access to the network protocol stacks and can manipulate packets easily and efficiently when required. This allows the user to craft very specific exploits that rely on very specific weaknesses in other systems. Most open source operating systems come with a free compiler such as gcc, which allows users to write their own code, compile it, and distribute it all over the Internet. gcc is one of the most powerful C/C++ compilers out there, and it is completely free and has been ported to several platforms.

Many of the best utilities exist and are available free for open source operating systems. Tools for scanning, packet capture and analysis, security auditing, and other related programs have been written directly for these operating systems and are not available in most cases for Windows- or Macintosh-based operating systems.

Another attraction in using open source operating systems is attitude and the perception of others. People who have never become familiar with a POSIX-compliant operating system, such as Linux or FreeBSD, are often intimidated by their complexity. Computer users taking the initiative to learn a powerful operating system such as Linux are usually looked on with respect by those afraid to venture into this territory.

OpenBSD

OpenBSD is billed as the most secure operating system freely available to anyone outside of government agencies. OpenBSD is a BSD–based (Berkeley Software Design), free, and secure version of the UNIX operating system. As I mentioned earlier, this OS has had a long history of excellent security, and, because of this, it makes an ideal operating system for a cracker. Any cracker worth his salt in the cracking community also needs to maintain his own high system security. What better operating system to use than the one with best record of security? Also, OpenBSD is completely open source, giving the same benefits I listed for Linux, NetBSD, and FreeBSD. The same utilities for those operating systems compile and run just fine in OpenBSD. OpenBSD will also run Linux, FreeBSD, and NetBSD software, if the need arises. If you want to be as secure as possible, out-of-the-box OpenBSD wins hands down.