Which attack method involves trying all possible combinations to gain access?

The attack method that involves trying all possible combinations to gain access is known as brute-force. In this approach, an attacker systematically attempts every possible password or encryption key until the correct one is found. This technique relies on the combination of factors such as the length and complexity of the password; longer and more complex passwords significantly increase the time required to successfully execute a brute-force attack.

Brute-force attacks are often automated using software that can rapidly test numerous combinations, making them highly effective against weak or commonly used passwords. Security measures such as account lockout mechanisms and CAPTCHAs are commonly implemented to mitigate the risk of brute-force attacks.

In contrast, phishing involves deceiving individuals into providing sensitive information, man-in-the-middle attacks intercept communications between two parties to eavesdrop or manipulate the conversation, and DDoS attacks aim to overwhelm a target's resources to make them unavailable. None of these methods are focused on systematically attempting combinations to gain access, which highlights why brute-force is the correct answer in this scenario.