What technique is often used to gain unauthorized access to passwords?

Brute force is a technique where an attacker systematically attempts all possible combinations of passwords until the correct one is found. This method relies on the computational power of machines to try numerous combinations quickly. It effectively bypasses security by leveraging time and technology, making it a common method for gaining unauthorized access to password-protected systems.

While other techniques like phishing, keylogging, and shoulder surfing involve different mechanics, they don't solely focus on the exhaustive trial-and-error approach characterizing brute force attacks. Phishing tricks individuals into revealing their credentials, keylogging captures keystrokes on a device, and shoulder surfing involves observing someone to obtain their password. Each method has its unique vectors and implications, but brute force stands out for its direct approach to cracking passwords by sheer persistence in trying combinations.