Aircrack-ng

Aircrack-ng is a suite of tools for assessing the security of Wi-Fi networks. It allows you to monitor, attack, test, and crack Wi-Fi security, helping you to evaluate how secure your Wi-Fi network really is. While it works best on Linux, it is also available for Windows, OS X, OpenBSD, FreeBSD, NetBSD, Solaris, and eComStation 2. The primary purpose of Aircrack-ng is to enable users to check the security of their own Wi-Fi networks, although it can also be used for more malicious purposes if one has the necessary hacking and programming skills.