Passwords is generally the first layer of security and authentication, password cracking techniques are very common the best techniques are guessing, dictionary based attack, brute force attack. There are so many tools are available to implement password cracking attack, backtrack and specially backtrack 5 contain different tools for online and offline password cracking. If your password is easy than a hacker or cracker can easily hack it by using guessing or other attack. Password cracking tutorial by using hydra so by looking at the tutorial you can easily understand about the weak and strong passwords.