diff options
Diffstat (limited to 'src/conf_mode/service_ids_suricata.py')
| -rwxr-xr-x | src/conf_mode/service_ids_suricata.py | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/src/conf_mode/service_ids_suricata.py b/src/conf_mode/service_ids_suricata.py new file mode 100755 index 000000000..49fbce244 --- /dev/null +++ b/src/conf_mode/service_ids_suricata.py @@ -0,0 +1,190 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2024 VyOS maintainers and contributors +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License version 2 or later as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +import os + +from sys import exit + +from vyos.base import Warning +from vyos.config import Config +from vyos.template import render +from vyos.utils.process import call +from vyos import ConfigError +from vyos import airbag +airbag.enable() + +config_file = '/run/suricata/suricata.yaml' +rotate_file = '/etc/logrotate.d/suricata' + +address_group_defaults = { + 'home-net': {'address': ['192.168.0.0/16','10.0.0.0/8','172.16.0.0/12']}, + 'external-net': {'group': ['!home-net']}, + 'http-servers': {'group': ['home-net']}, + 'smtp-servers': {'group': ['home-net']}, + 'sql-servers': {'group': ['home-net']}, + 'dns-servers': {'group': ['home-net']}, + 'telnet-servers': {'group': ['home-net']}, + 'aim-servers': {'group': ['external-net']}, + 'dc-servers': {'group': ['home-net']}, + 'dnp3-server': {'group': ['home-net']}, + 'modbus-client': {'group': ['home-net']}, + 'modbus-server': {'group': ['home-net']}, + 'enip-client': {'group': ['home-net']}, + 'enip-server': {'group': ['home-net']}, +} + +port_group_defaults = { + 'http-ports': {'port': ['80']}, + 'shellcode-ports': {'port': ['!80']}, + 'oracle-ports': {'port': ['1521']}, + 'ssh-ports': {'port': ['22']}, + 'dnp3-ports': {'port': ['20000']}, + 'modbus-ports': {'port': ['502']}, + 'file-data-ports': {'port': ['110', '143'], 'group': ['http-ports']}, + 'ftp-ports': {'port': ['21']}, + 'geneve-ports': {'port': ['6081']}, + 'vxlan-ports': {'port': ['4789']}, + 'teredo-ports': {'port': ['3544']}, +} + +def get_config(config=None): + if config: + conf = config + else: + conf = Config() + base = ['service', 'ids', 'suricata'] + if not conf.exists(base): + return None + + suricata = conf.get_config_dict(base, + get_first_key=True, + with_recursive_defaults=True) + + # Ensure minimal defaults are present + suricata['address-group'] = address_group_defaults | suricata.get('address-group', {}) + suricata['port-group'] = port_group_defaults | suricata.get('port-group', {}) + + return suricata + +# https://en.wikipedia.org/wiki/Topological_sorting#Depth-first_search +def topological_sort(source): + sorted_nodes = [] + permanent_marks = set() + temporary_marks = set() + + def visit(n, v): + if n in permanent_marks: + return + if n in temporary_marks: + raise ConfigError('At least one cycle exists in the referenced groups') + + temporary_marks.add(n) + + for m in v.get('group', []): + m = m.lstrip('!') + if m not in source: + raise ConfigError(f'Undefined referenced group "{m}"') + visit(m, source[m]) + + temporary_marks.remove(n) + permanent_marks.add(n) + sorted_nodes.append((n, v)) + + while len(permanent_marks) < len(source): + n = next(n for n in source.keys() if n not in permanent_marks) + visit(n, source[n]) + + return sorted_nodes + +def verify(suricata): + if not suricata: + return None + + if 'interface' not in suricata: + raise ConfigError('No interfaces configured') + + try: + topological_sort(suricata['address-group']) + except (ConfigError,StopIteration) as e: + raise ConfigError(f'Invalid address-group: {e}') + + try: + topological_sort(suricata['port-group']) + except (ConfigError,StopIteration) as e: + raise ConfigError(f'Invalid port-group: {e}') + +def generate(suricata): + if not suricata: + for file in [config_file, rotate_file]: + if os.path.isfile(file): + os.unlink(file) + + return None + + # Config-related formatters + def to_var(s:str): + return s.replace('-','_').upper() + + def to_val(s:str): + return s.replace('-',':') + + def to_ref(s:str): + if s[0] == '!': + return '!$' + to_var(s[1:]) + return '$' + to_var(s) + + def to_config(kind:str): + def format_group(group): + (name, value) = group + property = [to_val(property) for property in value.get(kind,[])] + group = [to_ref(group) for group in value.get('group',[])] + return (to_var(name), property + group) + return format_group + + # Format the address group + suricata['address-group'] = map(to_config('address'), + topological_sort(suricata['address-group'])) + + # Format the port group + suricata['port-group'] = map(to_config('port'), + topological_sort(suricata['port-group'])) + + render(config_file, 'ids/suricata.j2', {'suricata': suricata}) + render(rotate_file, 'ids/suricata_logrotate.j2', suricata) + return None + +def apply(suricata): + systemd_service = 'suricata.service' + if not suricata or 'interface' not in suricata: + # Stop suricata service if removed + call(f'systemctl stop {systemd_service}') + else: + Warning('To fetch the latest rules, use "update suricata"; ' + 'To periodically fetch the latest rules, ' + 'use the task scheduler!') + call(f'systemctl restart {systemd_service}') + + return None + +if __name__ == '__main__': + try: + c = get_config() + verify(c) + generate(c) + apply(c) + except ConfigError as e: + print(e) + exit(1) |