Dictionary Attacks

A dictionary attack is attempt to guess passwords by using well-known words or phrases.

Since most passwords are chosen by users, it stands to reason that most passwords are or contain common words. There are a little over a million words in the English language, while there are 308,915,776 possible combinations of 6 letters. Most attackers will take this into account when attempting to intrude on your system, and make use of word lists in combination with common password lists when trying to guess passwords.