The scenario describes an automated, trial-and-error attempt that triesall possible combinations of usernames and passwordsuntil a correct credential pair is found. This is the defining characteristic of abrute-force attack.
In digital forensics terminology, brute force is a direct password-guessing method that relies on exhaustive attempts (or systematically generated candidates) rather than tricking the user or exploiting a software flaw.
Investigators commonly recognize brute-force activity through artifacts such as repeated authentication failures in security logs, high-frequency login attempts from a single IP or distributed sources, account lockout events, and abnormal spikes in authentication traffic. In banking and web environments, it may also appear as repeated POST requests to login endpoints with varying credential pairs and consistent user-agent patterns, sometimes accompanied by throttling or CAPTCHA triggers.
The other options do not match the described "attempting all possible combinations" behavior.
Phishingobtains credentials by deception (fake emails/sites). ATrojan horsesteals data by running malicious code on the victim's system.Data manipulationfocuses on altering data integrity rather than credential guessing. Therefore, the correct attack type isBrute-force attack (A).