resolve_hostname_over_SOCKS.py

#!/usr/bin/env python3
import logging
import socket
import sys
from argparse import ArgumentParser, Namespace
from dns.resolver import Resolver
from os.path import exists

# Example Usage: proxychains -q python3 resolve_hostname_over_SOCKS.py --nameserver 10.10.10.10 --items SOMEWORKSTATION1.CONTOSO.LOCAL SOMEWORKSTATION2.CONTOSO.LOCAL
# Example Usage: proxychains -q python3 resolve_hostname_over_SOCKS.py --nameserver 10.10.10.10 --fileinput --items file_with_hostnames.txt


class DnsResolver:
    def __init__(self, options: Namespace):
        nameserver = options.nameserver
        self.resolver = Resolver()
        self.resolver.nameservers = [nameserver]

    def resolve(self, hostname: str) -> str:
        ip_addr = None
        logging.debug(f"Trying to resolve {repr(hostname)} at {repr(self.resolver.nameservers[0])}")

        try:
            answers = self.resolver.resolve(hostname, tcp=True)
            if len(answers) == 0:
                raise Exception()

            ip_addr = answers[0].to_text()
        except Exception:
            pass

        if ip_addr is None:
            try:
                ip_addr = socket.gethostbyname(hostname)
            except Exception:
                ip_addr = None

        if ip_addr is None:
            logging.warning(f"Failed to resolve: {hostname}")
            return hostname

        return ip_addr


def validateAllFiles(options: Namespace) -> bool:
    for item in options.items:
        if not exists(item):
            logging.warning(f"File doesn't exist, we're not going to continue. ({item})")
            return False

    return True


if __name__ == '__main__':
    parser = ArgumentParser("DNS Resolution over SOCKS proxy.")
    parser.add_argument("--nameserver", type=str, help="Nameserver IP address.", required=True)
    parser.add_argument("--fileinput", action="store_true", help="Whether this is expected to be a file input or not.", required=False)
    parser.add_argument("--items", nargs="+", help="List of items to use, either filename(s) or individual hosts.", required=True)
    parsedArgs = parser.parse_args()

    if parsedArgs.fileinput:
        if validateAllFiles(parsedArgs):
            currentDnsResolver = DnsResolver(parsedArgs)
            for file in parsedArgs.items:
                for endpoint in [line.strip() for line in open(file, 'r').readlines()]:
                    result = None

                    try:
                        result = currentDnsResolver.resolve(endpoint)
                    except Exception as e:
                        pass
                    finally:
                        if result is not None:
                            print(f"{endpoint}\t{result}")
        else:
            sys.exit(0)
    
    else:
        currentDnsResolver = DnsResolver(parsedArgs)
        for endpoint in parsedArgs.items:
            result = None

            try:
                result = currentDnsResolver.resolve(endpoint)
            except Exception as e:
                pass
            finally:
                if result is not None:
                    print(f"{endpoint}\t{result}")