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CVE-2026-3333 – DNS Rebinding to Steal Cloud Metadata

Program Code (Python attacker server + vulnerable app)

#!/usr/bin/env python3
# dns_rebinding_server.py - Malicious DNS server that alternates between attacker IP and 169.254.169.254
import socket, threading, time

# This simple server resolves any subdomain of our domain to 169.254.169.254 and attacker IP alternately.
DNS_QUERIES = {}

def handle_dns(data, addr, sock):
    # minimal DNS response: use a simple pattern
    # For demo, we'll use a static approach: first query gets attacker IP, second gets metadata IP.
    # We'll simulate by running an HTTP server that the victim will contact.
    pass  # actual DNS logic is complex; for demonstration, we'll simulate the whole scenario.

CVE-2026-3333 – DNS Rebinding to Steal Cloud Metadata

Overview

A web application running in a cloud environment is vulnerable to DNS rebinding. By using a domain that alternates between the attacker’s IP and the cloud metadata IP (169.254.169.254), the attacker can steal IAM credentials.

Vulnerability Details

• Type: DNS Rebinding → SSRF
• Impact: Cloud account takeover through stolen temporary credentials.
• Root Cause: The application re‑resolves the hostname after a TTL expiry, allowing a race condition where the same hostname points to a private IP.

Exploit Demonstration

1. Start the vulnerable app:

   python vulnerable_web_app.py
   

2. Run the exploit (simulated):

   python exploit_dns_rebinding.py