What is password spraying?

Password spraying is a type of cyberattack where an adversary attempts to gain unauthorized access to a large number of accounts by "spraying" a small set of commonly used passwords (such as "Password123" or "Winter2025!") across many different usernames. Unlike traditional brute-force attacks that relentlessly target a single account, password spraying is a "low-and-slow" technique designed to bypass account lockout policies and evade detection.

How password spraying attacks work

Attackers generally follow a systematic approach to maximize their chances of success while minimizing the risk of being caught:

• Reconnaissance: The attacker first compiles a list of valid usernames. This is often done by scraping public profiles on sites like LinkedIn, guessing email formats (e.g., [email protected]), or leveraging data from previous breaches.
• Selection of common passwords: Using lists of "most common passwords" (easily found online) or default credentials, the attacker chooses a limited set of high-probability password candidates.
• The "Spray": The attacker attempts to log in to each account on their list using only one password from their chosen set. By trying each account only once before moving on to the next password, they stay under the threshold of most automated lockout and security monitoring systems.
• Persistence & Escalation: Once a single account is compromised, the attacker can access sensitive information, search for further intelligence, or use the account for lateral movement to escalate their privileges within the network.

Why password spraying is dangerous

Password spraying preys on the predictable nature of human password habits. Because it is highly automated and distributed, it is difficult for standard security tools to identify it as a coordinated attack. A successful breach can lead to:

• Unauthorized data access: Exposure of intellectual property, customer databases, or financial records
• Account Takeover (ATO): Full control over user accounts, allowing attackers to manipulate internal workflows or launch further attacks
• Reputational damage: Loss of customer and employee trust following a breach

Comparative analysis

Password spraying vs. Brute force

In a traditional brute-force attack, the attacker targets a single account with thousands of password guesses. This is noisy and typically triggers an account lockout quickly. Password spraying reverses this, targeting thousands of accounts with just a few passwords, effectively staying "under the radar" of lockout mechanisms.

Password spraying vs. Credential stuffing

Credential stuffing involves using valid username-password pairs stolen from a previous breach to gain access to other services where the user may have reused those credentials. Password spraying does not require previously breached credentials; it relies on guessing weak, commonly used passwords.

How to prevent and mitigate password spray attacks

Password spray attacks rely on testing common passwords across many accounts to avoid triggering lockout thresholds. Preventing them requires layered controls that reduce the likelihood of successful guessing and detect abnormal login behavior early.

1. Enforce multi-factor authentication (MFA): Even if an attacker correctly guesses a password, MFA adds an additional verification step that blocks unauthorized access.
2. Strengthen password policies: Prohibit common, easily guessed, or previously breached passwords. Use banned password lists and encourage longer passphrases to reduce predictability.
3. Enable adaptive authentication controls: Configure identity and access management (IAM) systems to trigger additional verification (or block access) when login attempts originate from unusual locations, devices, or IP ranges.
4. Monitor authentication logs for anomalies: Watch for spikes in failed login attempts across multiple accounts, which can indicate a spray attack in progress.
5. Implement account lockout thresholds: Configure systems to temporarily lock accounts after a defined number of failed attempts. While attackers try to stay below these limits, lockout policies still serve as an important safeguard.

Secure your global fleet with Deel IT

Protecting your organization from password spraying requires a unified approach to security that starts with how you manage your devices and identities. Deel IT centralizes your hardware and access management, making it easy to enforce strong security policies—like mandatory MFA and SSO—across your entire global fleet. Whether you are managing full-time employees or international contractors, Deel IT gives you the visibility and control to harden your defenses against identity-based attacks from day one.

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FAQs

Why don't current security systems just block this automatically? Many systems are programmed to detect high-frequency failures on a single account. Because password spraying is "low-and-slow"—meaning it spreads the failures across hundreds of accounts over a longer period—it can look like normal, erratic user behavior to traditional monitoring tools.

How can I tell if my organization is currently being sprayed? Watch for a sudden surge in failed login attempts for non-existent accounts or a spike in logins from unexpected geographic locations. These are often the first signs that an attacker is testing your environment.