🔐 Broken Authentication

Understand how weak authentication mechanisms lead to full account compromise

What is Broken Authentication?

Broken Authentication refers to vulnerabilities in authentication mechanisms that allow attackers to gain unauthorized access to systems or user accounts. It’s part of the OWASP Top 10 and includes flaws like weak credential management, session hijacking, brute-force exposure, and improper implementation of login mechanisms.

🧩 Core Concepts & Risks

Common Issues:

  • Use of weak or predictable passwords
  • Credential stuffing due to reused passwords
  • Missing or ineffective rate-limiting on login forms
  • Exposed session IDs in URLs or logs
  • Session fixation or session ID not rotated after login
  • Insecure password reset flows

Potential Impact:

  • Full account takeover
  • Privilege escalation
  • Compromise of sensitive data
  • Persistence via stolen session tokens

🔍 Step-by-Step Exploitation Scenarios

1. Credential Stuffing Attack

Using leaked username/password pairs from previous breaches against a login page.

POST /login HTTP/1.1
Host: vulnerable-site.com
Content-Type: application/json

{
  "username": "admin@example.com",
  "password": "admin123"
}

If no rate-limiting or CAPTCHA is implemented, attackers can automate this process using tools like Burp Suite Intruder or Hydra.

2. Session ID Hijacking

Weak session handling can lead to session fixation or leakage via referer headers, logs, or URLs.

GET /dashboard?sessionID=abc123xyz HTTP/1.1
Cookie: sessionID=abc123xyz

If this ID is predictable or captured via MITM, the attacker can impersonate the user.

🌐 Real-World Case Study

In 2021, an online financial service provider was breached through a weak password reset implementation. Attackers exploited the lack of token expiration and predictable reset tokens to reset passwords of high-value accounts.

💡 Defensive Tips & Best Practices

📚 Recommended Tools & Resources