Weak Authentication
Last updated: January 12, 2026
Weak authentication allows attackers to gain unauthorized access through password guessing, session hijacking, or bypassing login controls.
Scan for This VulnerabilityWhat is Weak Authentication?
Authentication is your first line of defense. Weak configurations like no password requirements, missing rate limiting, or insecure sessions make it easy for attackers to compromise accounts. Even with otherwise secure code, weak auth can lead to complete account takeover.
Why It's Dangerous
This vulnerability can allow attackers to access sensitive data, compromise user accounts, or gain unauthorized control over your application. In AI-generated code, this issue is particularly common because security measures are often deprioritized in favor of rapid feature development.
Why AI Code Is Vulnerable
AI code generation tools focus on producing functional code quickly. They often generate patterns that work correctly but lack the defensive measures experienced security engineers would implement. This makes weak authentication particularly prevalent in vibe-coded applications.
Understanding the Technical Details
Weak Authentication is classified as a high-severity vulnerability because of its potential to cause significant damage to your application and users. Understanding the technical mechanics helps you recognize and prevent this issue in your own code.
This vulnerability typically occurs when security controls are either missing entirely, improperly configured, or incorrectly implemented. In many cases, the code appears to work correctly during development and testing, but the security flaw becomes exploitable once the application is deployed and accessible to malicious actors.
Attackers actively scan for this type of vulnerability using automated tools. Once discovered, exploitation can be rapid—often within hours of your application going live. The consequences range from data theft and account takeover to complete system compromise depending on the application's architecture.
For vibe-coded applications built with platforms like Lovable, Bolt.new, Replit, or v0.dev, this vulnerability appears in roughly 20-40% of deployments according to security research. The AI-generated patterns often follow insecure defaults that require manual security hardening.
How It Happens
- No minimum password length or complexity requirements
- Missing email verification
- No rate limiting on login endpoints
- Insecure session handling (no HttpOnly, Secure flags)
- Default auth configurations not hardened
Impact
Account takeover through credential stuffing
Brute force attacks succeed without rate limiting
Session hijacking if cookies are insecure
Fake accounts if email verification is missing
Data breaches through compromised accounts
How to Detect
- Try creating an account with a weak password
- Test login endpoint for rate limiting
- Check cookie flags in browser DevTools
- Verify email verification is required
- Run VAS to test auth configuration
How to Fix
Enforce password requirements
Require minimum length and complexity.
// Supabase Auth config
{
password_min_length: 8,
// Consider additional complexity rules
}Enable email verification
Require users to confirm their email before accessing the app.
Implement rate limiting
Limit login attempts to prevent brute force attacks.
// Rate limit example
const rateLimit = {
windowMs: 15 * 60 * 1000, // 15 minutes
max: 5 // 5 attempts per window
};Secure session cookies
Set appropriate flags on authentication cookies.
// Cookie settings
{
httpOnly: true, // Not accessible via JavaScript
secure: true, // HTTPS only
sameSite: 'lax' // CSRF protection
}Commonly Affected Platforms
Prevention Best Practices
The most effective approach to weak authentication is prevention. Implementing security measures during development is significantly easier and less costly than remediating vulnerabilities after deployment.
Security-First Development
When using AI code generation tools, always review the generated code for security implications. AI tools prioritize functionality over security, so treat all generated code as requiring security review. Establish a checklist of security requirements specific to your application type and verify each before deployment.
Continuous Security Testing
Integrate security scanning into your development workflow. Run scans after major code changes, before deployments, and on a regular schedule for production applications. Early detection of vulnerabilities reduces remediation costs and prevents potential breaches.
Defense in Depth
Never rely on a single security control. Implement multiple layers of protection so that if one control fails, others still protect your application. For example, combine authentication, authorization, input validation, and output encoding to create comprehensive protection against attacks.
Stay Informed
Security threats evolve constantly. Follow security researchers, subscribe to vulnerability databases, and monitor your dependencies for known issues. Understanding emerging threats helps you proactively protect your applications before attackers exploit new techniques.
Is Your App Vulnerable?
VAS automatically scans for weak authentication and provides detailed remediation guidance with code examples. Our scanner specifically targets vulnerabilities common in AI-generated applications.
Scans from $5, results in minutes. Get actionable results with step-by-step fix instructions tailored to your stack.
Get Starter ScanFrequently Asked Questions
What's a good minimum password length?
NIST recommends minimum 8 characters, but 12+ is better. Length matters more than complexity - 'correct-horse-battery-staple' is stronger than 'P@ssw0rd!'. Consider using a password strength meter (like zxcvbn) instead of rigid complexity rules.
How many login attempts before lockout?
5 attempts per 15 minutes is a common balance. Too strict locks out legitimate users who forgot passwords; too loose allows brute force. Consider progressive delays: 1 second after attempt 3, 5 seconds after 4, 30 seconds after 5, then account lockout requiring email verification.
Should I use JWT or sessions?
Both can be secure if implemented correctly. Sessions (server-stored) are easier to invalidate but need server state. JWTs (client-stored) are stateless but harder to revoke. For most apps: use your auth provider's default (Supabase uses JWTs, many frameworks use sessions).
Is magic link authentication more secure than passwords?
Magic links shift risk from weak passwords to email security. They prevent password reuse attacks but depend on email being secure. Good for: apps with occasional users. Bad for: frequent logins (annoying UX). Consider offering both options.