| 1 | #!/usr/bin/python3 |
| 2 | # Copyright (C) 2025, SOCFortress LLC. |
| 3 | # All rights reserved. |
| 4 | |
| 5 | # This program is free software; you can redistribute it |
| 6 | # and/or modify it under the terms of the GNU General Public |
| 7 | # License (version 2) as published by the FSF - Free Software |
| 8 | # Foundation. |
| 9 | |
| 10 | import datetime |
| 11 | import ipaddress |
| 12 | import json |
| 13 | import os |
| 14 | import subprocess |
| 15 | import sys |
| 16 | |
| 17 | LOG_FILE = ( |
| 18 | "C:\\Program Files (x86)\\ossec-agent\\active-response\\active-responses.log" |
| 19 | if os.name == "nt" |
| 20 | else "/var/ossec/logs/active-responses.log" |
| 21 | ) |
| 22 | |
| 23 | COMMANDS = {"add": 0, "delete": 1, "continue": 2, "abort": 3} |
| 24 | |
| 25 | OS_SUCCESS = 0 |
| 26 | OS_INVALID = -1 |
| 27 | |
| 28 | |
| 29 | class Message: |
| 30 | def __init__(self, alert="", command=0): |
| 31 | self.alert = alert |
| 32 | self.command = command |
| 33 | |
| 34 | |
| 35 | def write_debug_file(ar_name, msg): |
| 36 | """Writes a debug message to the log file.""" |
| 37 | with open(LOG_FILE, mode="a") as log_file: |
| 38 | log_msg = { |
| 39 | "timestamp": datetime.datetime.now().strftime("%Y/%m/%d %H:%M:%S"), |
| 40 | "active_response": "windows_firewall", |
| 41 | "message": json.loads(msg) if isinstance(msg, str) and msg.strip().startswith("{") else msg, |
| 42 | } |
| 43 | log_file.write(json.dumps(log_msg) + "\n") |
| 44 | |
| 45 | |
| 46 | def setup_and_check_message(argv): |
| 47 | """Reads and validates the input message.""" |
| 48 | input_str = next(sys.stdin, "") |
| 49 | write_debug_file(argv[0], input_str) |
| 50 | try: |
| 51 | data = json.loads(input_str) |
| 52 | except ValueError: |
| 53 | write_debug_file(argv[0], "Decoding JSON has failed, invalid input format") |
| 54 | return Message(command=OS_INVALID) |
| 55 | command = COMMANDS.get(data.get("command"), OS_INVALID) |
| 56 | if command == OS_INVALID: |
| 57 | write_debug_file(argv[0], "Not valid command: " + data.get("command")) |
| 58 | return Message(alert=data, command=command) |
| 59 | |
| 60 | |
| 61 | def is_valid_ipv4(ip): |
| 62 | """Checks if an IP address is valid and not private.""" |
| 63 | try: |
| 64 | ip_obj = ipaddress.IPv4Address(ip) |
| 65 | return ip_obj.is_global |
| 66 | except ipaddress.AddressValueError: |
| 67 | return False |
| 68 | |
| 69 | |
| 70 | def block_ip(ip): |
| 71 | """Blocks an IP address on the Windows Firewall.""" |
| 72 | try: |
| 73 | subprocess.run( |
| 74 | [ |
| 75 | r"C:\Windows\System32\netsh", |
| 76 | "advfirewall", |
| 77 | "firewall", |
| 78 | "add", |
| 79 | "rule", |
| 80 | f"name=SOCFortress Block Outbound {ip}", |
| 81 | "dir=out", |
| 82 | "action=block", |
| 83 | f"remoteip={ip}", |
| 84 | ], |
| 85 | check=True, |
| 86 | ) |
| 87 | return f"Blocked IP {ip} on Windows Firewall" |
| 88 | except subprocess.CalledProcessError as e: |
| 89 | return f"Failed to block IP {ip} on Windows Firewall: {e}" |
| 90 | |
| 91 | |
| 92 | def remove_ip(ip): |
| 93 | """Removes a blocked IP address from the Windows Firewall.""" |
| 94 | try: |
| 95 | subprocess.run( |
| 96 | [r"C:\Windows\System32\netsh", "advfirewall", "firewall", "delete", "rule", f"name=SOCFortress Block Outbound {ip}"], |
| 97 | check=True, |
| 98 | ) |
| 99 | return f"Removed blocked IP {ip} from Windows Firewall" |
| 100 | except subprocess.CalledProcessError as e: |
| 101 | return f"Failed to remove blocked IP {ip} from Windows Firewall: {e}" |
| 102 | |
| 103 | |
| 104 | def extract_alert_info(msg, argv): |
| 105 | """Extracts the action and IP from the alert message.""" |
| 106 | try: |
| 107 | alert = msg.alert["parameters"]["alert"] |
| 108 | action = alert["action"] |
| 109 | ip = alert["ip"] |
| 110 | except KeyError as e: |
| 111 | write_debug_file(argv[0], f"Missing key in alert message: {str(e)}") |
| 112 | sys.exit(OS_INVALID) |
| 113 | return action, ip |
| 114 | |
| 115 | |
| 116 | def main(argv): |
| 117 | write_debug_file(argv[0], {"status": "Started"}) |
| 118 | msg = setup_and_check_message(argv) |
| 119 | if msg.command < 0: |
| 120 | sys.exit(OS_INVALID) |
| 121 | if msg.command == COMMANDS["add"]: |
| 122 | action, ip = extract_alert_info(msg, argv) |
| 123 | if not is_valid_ipv4(ip): |
| 124 | write_debug_file(argv[0], {"status": "failed", "message": f"Invalid IP address {ip}"}) |
| 125 | sys.exit(OS_INVALID) |
| 126 | if action == "block": |
| 127 | write_debug_file(argv[0], block_ip(ip)) |
| 128 | if action == "unblock": |
| 129 | write_debug_file(argv[0], remove_ip(ip)) |
| 130 | elif msg.command == COMMANDS["delete"]: |
| 131 | # Optionally, include logic here to remove the firewall rule if necessary |
| 132 | pass |
| 133 | else: |
| 134 | write_debug_file(argv[0], "Invalid command") |
| 135 | write_debug_file(argv[0], "Ended") |
| 136 | sys.exit(OS_SUCCESS) |
| 137 | |
| 138 | |
| 139 | if __name__ == "__main__": |
| 140 | main(sys.argv) |