CVE-2026-9545：libcurl HTTP/3 SSL会话缓存导致敏感信息泄露

#!/usr/bin/env python3 """ CVE-2026-9545 PoC - Demonstrates the vulnerability concept This PoC simulates the attack scenario where an attacker intercepts HTTP/3 connections and exploits SSL session caching with early data. Note: This is a conceptual PoC. Actual exploitation requires: - Network MITM capability (e.g., ARP spoofing, DNS hijacking) - A rogue HTTP/3 server without valid TLS certificate - A vulnerable libcurl client with specific options enabled """ import socket import ssl import struct # Vulnerable libcurl configuration that triggers CVE-2026-9545 VULNERABLE_CURL_OPTIONS = { "CURLOPT_SSL_SESSIONID_CACHE": 1, # Enabled (default) "CURLOPT_SSL_OPTIONS": "CURLSSLOPT_EARLYDATA", # Early data enabled "CURLOPT_HTTP_VERSION": "CURL_HTTP_VERSION_3", # HTTP/3 } def simulate_attack_scenario(): """ Simulates the attack chain: 1. Legitimate HTTP/3 connection establishes SSL session 2. Attacker replaces the server 3. Client reuses cached session with early data 4. Sensitive data leaks before cert verification fails """ print("[*] CVE-2026-9545 Attack Simulation") print(f"[*] Vulnerable options: {VULNERABLE_CURL_OPTIONS}") # Step 1: Establish legitimate connection print("[+] Step 1: Client connects to legitimate HTTP/3 server") print(" -> TLS handshake completes successfully") print(" -> SSL session cached for reuse") # Step 2: Attacker intercepts print("[+] Step 2: Attacker performs MITM, replaces server") print(" -> Rogue server has NO valid TLS certificate") # Step 3: Client attempts reconnection print("[+] Step 3: Client initiates second transfer to same host") print(" -> libcurl reuses cached SSL session") print(" -> Early data (0-RTT) sent BEFORE cert verification") # Step 4: Data leakage print("[+] Step 4: Sensitive request data sent to attacker's server") print(" -> Certificate verification fails AFTER data is sent") print(" -> Confidential information compromised!") print("\n[!] Vulnerability confirmed: sensitive data leaked before cert validation") def vulnerable_curl_command(): """ Command that would trigger the vulnerability with a vulnerable libcurl version. """ cmd = ( 'curl -V # Check if libcurl version is vulnerable\n' '# Vulnerable usage pattern:\n' 'curl --http3-only \\\n' ' --ssl-allow-earlydata \\\n' ' https://target.example.com/api/sensitive-endpoint \\\n' ' -H "Authorization: Bearer SECRET_TOKEN" \\\n' ' -d \'{"password": "PASSWORD123"}\'\n\n' '# The second request to the same host (after MITM) will leak data\n' '# before certificate verification failure is enforced' ) return cmd if __name__ == "__main__": simulate_attack_scenario() print("\n" + "="*60) print("Vulnerable curl command pattern:") print("="*60) print(vulnerable_curl_command())