Password Spraying

What is Password Spraying?

Password spraying is a credential-based attack where attackers test a small number of commonly used passwords against many different accounts rather than trying many passwords against a single account. This technique helps attackers avoid account lockout mechanisms that typically trigger after multiple failed login attempts on a single account.

Unlike brute force attacks that target individual accounts, password spraying spreads login attempts across multiple accounts, making it harder to detect and more likely to succeed.

How Password Spraying Works

1. Password Selection: Attackers compile a list of common passwords (e.g., "Password123", "Winter2025", "Company123")
2. Account Collection: Attackers gather usernames from public sources or previous breaches
3. Slow and Steady: Attackers test one password against many accounts, then wait before trying another
4. Avoid Detection: The delay between attempts helps evade security systems
5. Account Compromise: Successful logins grant access to compromised accounts

Key Characteristics

• Low and Slow: Spreads login attempts over time to avoid detection
• Common Passwords: Targets passwords likely to be used by multiple users
• Broad Targeting: Tests passwords against many accounts rather than focusing on one
• Evasion: Designed to bypass account lockout policies
• Automated: Uses tools to systematically test credentials

Common Targets

Password spraying attacks frequently target:

• Corporate email systems (Microsoft 365, Outlook Web Access)
• Virtual Private Networks (VPNs)
• Remote Desktop Protocol (RDP) services
• Single Sign-On (SSO) portals
• Cloud services and collaboration platforms
• Internal company applications
• API endpoints with authentication

Real-World Examples

• 2018 U.S. Government: Attackers used password spraying against multiple agencies
• 2020 Citrix: Password spraying led to unauthorized access to corporate systems
• 2021 Microsoft: State-sponsored actors used password spraying against cloud services
• 2022 Cisco: Attackers gained initial access through password spraying
• 2023 Okta: Multiple organizations compromised through password spraying attacks

Prevention and Mitigation

For Organizations:

• Multi-Factor Authentication (MFA): Require additional verification beyond passwords
• Account Lockout: Implement temporary lockouts after failed attempts
• Password Policies: Enforce strong, unique passwords and regular changes
• Anomaly Detection: Monitor for unusual login patterns across multiple accounts
• Rate Limiting: Restrict the number of login attempts from a single IP
• CAPTCHA: Implement challenge-response tests for suspicious activity
• Password Blacklists: Block commonly used and compromised passwords
• Behavioral Analytics: Detect unusual access patterns and timing

For Users:

• Strong Passwords: Use complex, unique passwords for each account
• Password Managers: Utilize tools to generate and store secure passwords
• Multi-Factor Authentication: Enable MFA wherever available
• Monitor Accounts: Regularly check for suspicious login activity
• Security Awareness: Be cautious of phishing attempts that steal credentials

Password Spraying vs. Other Attacks

Tools and Techniques Used

Attackers commonly use:

• Automation Tools: Custom scripts, Hydra, Medusa, Burp Suite
• Password Lists: Common passwords, seasonal passwords, company-specific passwords
• Proxy Services: Rotate IP addresses to avoid detection
• Credential Databases: Lists of usernames from public sources or breaches
• Timing Techniques: Spread attempts over hours or days to avoid detection
• Context Awareness: Target specific industries or organizations with tailored passwords

Industry-Specific Passwords

Attackers often customize their password lists based on the target industry:

Legal and Ethical Considerations

Password spraying is illegal in most jurisdictions and considered a form of computer intrusion. Organizations that fail to protect against these attacks may face:

• Legal Liability: Potential lawsuits from affected users or customers
• Regulatory Fines: Penalties under data protection laws (GDPR, CCPA, HIPAA)
• Reputational Damage: Loss of customer and partner trust
• Operational Disruption: Downtime and recovery costs from security incidents
• Intellectual Property Theft: Loss of sensitive business information

Future Trends

As security measures evolve, password spraying techniques are becoming more sophisticated:

• AI-Powered Attacks: Machine learning to identify password patterns and predict likely credentials
• Context-Aware Spraying: Using organizational information to create targeted password lists
• Slow Burn Attacks: Spreading attempts over weeks or months to avoid detection
• Multi-Channel Attacks: Combining password spraying with phishing or social engineering
• Cloud Targeting: Increased focus on cloud services and remote access solutions
• Credential Harvesting: Using successful compromises to gather more credentials for future attacks