A credential attack is any attempt to gain account access by testing usernames and passwords rather than exploiting code directly. Common forms include password guessing, password spraying, and credential stuffing, where attackers reuse credentials leaked in other breaches. These attacks succeed when people choose weak passwords, reuse them across services, or leave default credentials unchanged.
Credential attacks matter because they target the identity layer that protects email, admin consoles, VPNs, cameras, cloud apps, and other high-value systems. They often produce valid logins, which makes them harder to block than malware alone. Defenders look for repeated failures, many logins from one source, logins across many accounts, and impossible travel or unusual device patterns. Strong passwords, multifactor authentication, rate limiting, lockouts, and detection of reused credentials reduce the risk.