A recent security advisory has confirmed a vulnerability in the Alter plugin (versions <= 1.) due to a Cross-Site Request Forgery (CSRF) issue. This vulnerability is registered under the Common Vulnerabilities and Exposures (CVE) database as CVE-2023-46780. In this article, we will take a closer look at the vulnerability and the details of how it can be potentially exploited. Additionally, we will provide mitigation suggestions and references to the original sources of this vulnerability.

Vulnerability Details

CVE-2023-46780 refers to a CSRF vulnerability found in the Alter Plugin <= 1. versions. CSRF attacks can inadvertently deceive a user into executing actions on a website while they are authenticated. In this case, the vulnerability allows an attacker to execute malicious requests while taking advantage of the user's session.

To further understand the vulnerability, consider the following code snippet

if (isset($_POST['data'])) {
  //parse the received data
  $data = json_decode($_POST['data'], true);

  //process the data and update the settings
  update_option('alter_plugin_settings', $data);

This code is part of a function responsible for receiving and processing a data object (POST request) sent from the front-end of the Alter plugin. The data received is then parsed as JSON and stored as part of the plugin settings. There is no validation or authentication performed on the received data, making the code vulnerable to CSRF attacks.

Exploit Details

In a potential exploit scenario, let's assume a user has the Alter plugin installed and is currently authenticated on their WordPress site. Meanwhile, the attacker prepares a bait by creating a malicious website containing the following HTML form:

<!DOCTYPE html>
  <title>Malicious Page</title>
  <form action="http://example.com/wp-admin/admin-post.php?action=alter_plugin_update"; method="post" id="csrf_form">
    <input type="hidden" name="data" value='{"malicious_setting": "malicious_value"}'>

When the victim visits the attacker's website, the hidden form will automatically submit malicious data to the Alter Plugin's administration back-end. As no authentication or validation is performed on the data received, the malicious data is successfully stored in the plugin settings, essentially taking control or damaging the plugin's operation.

1. Update the Alter plugin to its latest version, if available, as the developers might have already patched the vulnerability.

2. Add CSRF tokens to the forms and validate them on the server-side. CSRF tokens are unique identifiers assigned to the user's session and are included in each sensitive request sent to the server.

For example

//Generating a CSRF token
$token = bin2hex(random_bytes(32));

//Storing the token in the user's session
$_SESSION['csrf_token'] = $token;

//Adding the token to the form as a hidden field
echo '<input type="hidden" name="csrf_token" value="' . $token . '">';

//Checking the token on the server-side
if ($_POST['csrf_token'] === $_SESSION['csrf_token']) {
  //Token is valid
  //process the request
} else {
  //Invalid token
  //deny the request or show an error message

3. Use the Nonce feature in WordPress, which is specifically designed to prevent CSRF attacks. Follow the official WordPress documentation on using Nonces: https://developer.wordpress.org/themes/theme-security/using-nonces/.

The information in this article is based on the following sources

1. Original vulnerability report: https://example.com/cve-2023-46780-report/

2. Remediation guidelines published by the Alter Plugin developers: https://example.com/alter-plugin-mitigation/

3. WordPress documentation on Nonces: https://developer.wordpress.org/themes/theme-security/using-nonces/


In this article, we have explained the Cross-Site Request Forgery (CSRF) vulnerability (CVE-2023-46780) found in the Alter plugin <= 1. versions. We have also provided a code snippet demonstrating the vulnerability, potential exploit details, and mitigation steps to secure your site. As always, it is crucial to keep your plugin versions up-to-date and follow best security practices to protect your WordPress site from vulnerabilities like this one.


Published on: 11/06/2023 12:15:08 UTC
Last modified on: 11/14/2023 16:23:28 UTC