Account activity review is the process of checking sign-ins, password resets, privilege changes, file access, and other account events for signs of misuse. Security teams use it to spot anomalies such as logins from unfamiliar locations, repeated failed attempts, new forwarding rules, or sudden changes to permissions. It is a basic but important control because many intrusions start with a valid username and password, not malware.
In real attacks, threat actors often try to blend in after gaining access, so the first clues may appear in authentication or audit logs rather than in obvious alerts. Regular review can expose credential theft, insider abuse, and account takeover early, limiting damage. In defense, this review supports incident response, helps confirm whether a public claim reflects real access, and provides evidence for deciding whether to disable accounts, force resets, or tighten multifactor authentication.