Credential misuse is the unauthorized use of valid login details, API keys, session tokens, or other authentication material. Unlike brute-force attacks, it does not require guessing a password; the attacker acts as a legitimate user because the credential itself is valid. This can happen after phishing, malware theft, weak sharing practices, or poor token handling.
It matters because access controls often trust authenticated accounts. When credentials are misused, an attacker can send messages, change settings, approve actions, or read sensitive data while blending in with normal activity. In defense, security teams reduce this risk with multi-factor authentication, short-lived tokens, least-privilege access, strong logging, and anomaly detection for unusual locations, devices, or message patterns. In trusted systems such as emergency alert platforms, credential misuse can turn a protected channel into a source of false but believable warnings.