CVE-2009-1122

What is this vulnerability?

CVE-2009-1122 is categorized as a unknown Improper Authentication flaw. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

The WebDAV extension in Microsoft Internet Information Services (IIS) 5.0 on Windows 2000 SP4 does not properly decode URLs, which allows remote attackers to bypass authentication, and possibly read or create files, via a crafted HTTP request, aka "IIS 5.0 WebDAV Authentication Bypass Vulnerability," a different vulnerability than CVE-2009-1535.

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

Impact on Systems

✅ Unauthorized Data Access: Attackers can bypass authorization controls to access other users' data or administrative endpoints.

✅ Account Takeover: Broken authentication or authorization may enable full account compromise without valid credentials.

✅ API Abuse: Exploiting this vulnerability enables mass data harvesting or destructive operations through unprotected API endpoints.

How to Fix and Mitigate CVE-2009-1122

1. Apply Vendor Patches: Upgrade affected components to their latest, non-vulnerable versions immediately.
2. Implement Input Validation: Ensure all user-supplied data is validated, sanitized, and type-checked before processing.
3. Deploy Runtime Protection: Use Precogs continuous monitoring to detect exploitation attempts in real time.
4. Audit Dependencies: Review and update all third-party libraries and transitive dependencies.

Defending with Precogs AI

Microsoft IIS 5.0 WebDAV extension contains an authentication bypass vulnerability. Attackers append a Unicode-encoded character to the HTTP request, bypassing password checks to access restricted directories. Precogs API Security Engine detects logic flaws and encoding bypasses in authentication handlers.

Use Precogs to continuously scan your codebase, binaries, APIs, and infrastructure for this vulnerability class and related attack patterns. Our AI-powered detection engine combines static analysis with threat intelligence to identify exploitable weaknesses before attackers do.

Start scanning with Precogs →

Vulnerability Code Signature

Attack Data Flow

Vulnerable Code Pattern

// ❌ VULNERABLE: Improper Authentication
app.post('/login', (req, res) => {
  const { username, password } = req.body;
  // Taint sink: weak or bypassable validation
  if (username === 'admin' || password === 'secret') {
    req.session.authenticated = true;
    res.send('Logged in');
  }
});

Secure Code Pattern

// ✅ SECURE: Robust Authentication
const bcrypt = require('bcrypt');
app.post('/login', async (req, res) => {
  const { username, password } = req.body;
  const user = await db.getUser(username);
  // Sanitized validation: secure password comparison
  if (user && await bcrypt.compare(password, user.passwordHash)) {
    req.session.authenticated = true;
    res.send('Logged in');
  } else {
    res.status(401).send('Invalid credentials');
  }
});

How Precogs Detects This

Precogs API Security Engine comprehensively audits endpoints to ensure strict authentication boundaries and secure logic.\n