#!/usr/bin/env python3
# For authorized testing in lab/CTF environments only
"""SMB vulnerability assessment agent using Impacket for enumeration and signing checks."""

import argparse
import json
import logging
import sys
from datetime import datetime
from typing import List

try:
    from impacket.smbconnection import SMBConnection
    from impacket.nmb import NetBIOSTimeout
    from impacket import smbconnection
except ImportError:
    sys.exit("impacket is required: pip install impacket")

logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(message)s")
logger = logging.getLogger(__name__)


def check_smb_port(target: str, port: int = 445, timeout: int = 5) -> bool:
    """Check if SMB port is open on the target."""
    import socket
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.settimeout(timeout)
        s.connect((target, port))
        s.close()
        return True
    except (socket.timeout, ConnectionRefusedError, OSError):
        return False


def enumerate_smb(target: str, username: str = "", password: str = "",
                   domain: str = "") -> dict:
    """Enumerate SMB service information on a target host."""
    result = {
        "target": target,
        "port_open": check_smb_port(target),
        "os_info": "",
        "smb_version": "",
        "signing_required": True,
        "shares": [],
        "error": None,
    }
    if not result["port_open"]:
        result["error"] = "SMB port 445 not reachable"
        return result

    try:
        smb = SMBConnection(target, target, sess_port=445, timeout=10)
        smb.negotiateSession()
        result["signing_required"] = smb.isSigningRequired()
        result["smb_version"] = f"SMBv{smb.getDialect()}"

        if username:
            smb.login(username, password, domain)
            result["os_info"] = smb.getServerOS()
            shares = smb.listShares()
            for share in shares:
                share_name = share["shi1_netname"][:-1]
                share_type = share["shi1_type"]
                result["shares"].append({
                    "name": share_name,
                    "type": share_type,
                    "remark": share["shi1_remark"][:-1] if share["shi1_remark"] else "",
                })
            smb.logoff()
        else:
            try:
                smb.login("", "")
                result["null_session"] = True
                shares = smb.listShares()
                for share in shares:
                    result["shares"].append({"name": share["shi1_netname"][:-1]})
                smb.logoff()
            except Exception:
                result["null_session"] = False

        smb.close()
    except Exception as exc:
        result["error"] = str(exc)
        logger.warning("SMB enum failed on %s: %s", target, exc)

    return result


def scan_network(targets: List[str], username: str = "", password: str = "",
                  domain: str = "") -> List[dict]:
    """Scan multiple targets for SMB services."""
    results = []
    for target in targets:
        logger.info("Scanning %s...", target)
        info = enumerate_smb(target, username, password, domain)
        results.append(info)
    return results


def find_relay_targets(results: List[dict]) -> List[str]:
    """Identify hosts where SMB signing is not required (relay targets)."""
    targets = [r["target"] for r in results if not r.get("signing_required", True) and r["port_open"]]
    logger.info("Found %d SMB relay targets (signing disabled)", len(targets))
    return targets


def check_null_sessions(results: List[dict]) -> List[str]:
    """Identify hosts accepting null SMB sessions."""
    return [r["target"] for r in results if r.get("null_session")]


def generate_report(results: List[dict]) -> dict:
    """Generate SMB vulnerability assessment report."""
    smb_hosts = [r for r in results if r["port_open"]]
    relay_targets = find_relay_targets(results)
    null_hosts = check_null_sessions(results)

    findings = []
    if relay_targets:
        findings.append(
            f"HIGH: {len(relay_targets)}/{len(smb_hosts)} hosts have SMB signing disabled"
        )
    if null_hosts:
        findings.append(
            f"MEDIUM: {len(null_hosts)} hosts accept null SMB sessions"
        )

    all_shares = []
    for r in smb_hosts:
        for s in r.get("shares", []):
            all_shares.append({"host": r["target"], "share": s["name"]})

    return {
        "assessment_date": datetime.utcnow().isoformat(),
        "total_targets_scanned": len(results),
        "smb_hosts_found": len(smb_hosts),
        "signing_disabled_hosts": relay_targets,
        "null_session_hosts": null_hosts,
        "accessible_shares": all_shares,
        "findings": findings,
    }


def expand_cidr(cidr: str) -> List[str]:
    """Expand a CIDR range to individual IPs (supports /24 and smaller)."""
    import ipaddress
    try:
        network = ipaddress.ip_network(cidr, strict=False)
        return [str(ip) for ip in network.hosts()]
    except ValueError:
        return [cidr]


def main():
    parser = argparse.ArgumentParser(description="SMB Vulnerability Assessment Agent")
    parser.add_argument("--targets", nargs="+", required=True, help="Target IPs or CIDR ranges")
    parser.add_argument("--username", default="", help="Domain username")
    parser.add_argument("--password", default="", help="Password")
    parser.add_argument("--domain", default="", help="Domain name")
    parser.add_argument("--output", default="smb_report.json")
    args = parser.parse_args()

    all_targets = []
    for t in args.targets:
        all_targets.extend(expand_cidr(t))

    results = scan_network(all_targets, args.username, args.password, args.domain)
    report = generate_report(results)

    with open(args.output, "w") as f:
        json.dump(report, f, indent=2)
    logger.info("Report saved to %s", args.output)
    print(json.dumps(report, indent=2))


if __name__ == "__main__":
    main()