What password spraying is
A password-spraying attack is a technique where an attacker tries a small number of very common passwords against a large number of different accounts, rather than hammering one account with many guesses. The idea is that in any big group of users, some will have chosen a weak, common password. By spraying a common guess across many accounts, the attacker is likely to get into at least a few, while avoiding the defenses that catch repeated guessing.
Avoiding account lockouts
Many systems lock an account or trigger alarms after several failed login attempts on it, which stops traditional guessing attacks that focus on one account. Password spraying sidesteps this cleverly. By trying just one or two passwords per account across many accounts, it stays under the threshold that triggers a lockout on any single account, letting the attacker keep going without setting off the usual alarms.
Password spraying versus brute force
A traditional brute-force attack tries many passwords against one account, which is why lockouts defeat it. Password spraying flips this: few passwords, many accounts. This reversal is what makes it effective against defenses built to stop repeated attempts on individuals. It exploits the fact that, across a large population, common weak passwords are statistically certain to be in use somewhere, even if no single account is attacked heavily.
Why it works
Password spraying succeeds because people keep choosing predictable, common passwords despite all advice. An attacker armed with a list of the most popular passwords and a large set of usernames can reliably break into some accounts. The weakness it exploits is human, not technical: the persistence of weak, widely reused passwords. This is why it remains a common and effective attack against organizations and services.
How to defend against it
Defenses focus on removing the weaknesses the attack relies on. Requiring strong, unique passwords and blocking common ones makes spraying far less likely to succeed. Two-factor authentication or passkeys add a second barrier, so a guessed password alone is not enough. Monitoring for many failed logins across accounts, not just on one, can detect spraying in progress. Together these greatly reduce the threat.
The bottom line
A password-spraying attack tries a few common passwords across many accounts to slip past lockout defenses that stop repeated guessing on a single account. It reverses the usual brute-force approach and exploits the persistence of weak, common passwords. Understanding it explains a common attack and why strong, unique passwords plus two-factor authentication or passkeys are such effective defenses against it.
Related on Skillo
See also: What is a password manager? Explained, What is two-factor authentication (2FA)?.
Sources
Published date reflects the original event date (2026-10-23). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.
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