You have found that someone has been attempting to log on to your web server. The person has tried a wide range of likely passwords. Which of the following types of attack is this?

This is an example of an online brute-force dictionary attack. Dictionary attacks use common passwords as well as common substitutions to attempt to break into a system or service. Back-off algorithms that lock out attackers after a small number of incorrect password attempts can help slow or stop dictionary attacks and other brute-force password attacks. Rainbow tables are tables of precomputed hashes. The birthday attack is a method for generating collisions of hashes. Finally, no spoofing is indicated in this scenario.