CVE-2025-68911

Executive Summary

CVE-2025-68911 is a Missing Authorization vulnerability in the Solace WordPress plugin (by solacewp), affecting versions through 2.1.16. This flaw allows unauthenticated attackers to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or privilege escalation. The vulnerability is classified as a WordPress ecosystem issue, not related to Apache or Nginx. No public exploit code or patch is currently available, and the EPSS score is 0.0%, indicating low exploitation likelihood at this time.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users should verify the integrity of their plugin files and monitor for updates from the vendor. Since no patch is available, consider disabling the plugin until a fix is released.

CVSS Breakdown & Threat Level

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

The threat level is Medium, as the vulnerability allows unauthorized access but does not directly lead to full system compromise.

Deep Dive & Mechanics

The vulnerability resides in the Solace WordPress plugin's access control mechanisms. The plugin fails to properly validate user permissions before executing sensitive actions, allowing attackers to bypass authentication checks. This is a classic Missing Authorization (CWE-862) issue, where the application does not enforce proper access controls on certain endpoints or functions.

The flaw likely exists in AJAX handlers or REST API endpoints that are intended for authenticated users but are exposed without proper capability checks. Attackers can craft requests to these endpoints to perform actions such as modifying plugin settings, accessing private data, or escalating privileges.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described generically:

Vulnerable Code (PHP):

add_action('wp_ajax_nopriv_solace_action', 'solace_handle_action');
function solace_handle_action() {
    // No permission check
    update_option('solace_settings', $_POST['settings']);
}

Patched Code (Hypothetical):

add_action('wp_ajax_solace_action', 'solace_handle_action');
function solace_handle_action() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized');
    }
    update_option('solace_settings', $_POST['settings']);
}

The patched version adds a capability check (current_user_can) and restricts the action to authenticated users only.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target WordPress site with Solace plugin <= 2.1.16
• Network access to the target

Exploitation Steps:

1. Identify vulnerable endpoints by analyzing plugin source code or using fuzzing.
2. Craft a request to the vulnerable AJAX endpoint without authentication:

   curl -X POST http://target/wp-admin/admin-ajax.php \
        -d 'action=solace_action&settings[malicious]=value'
   

3. Verify unauthorized access by checking if the action was performed (e.g., settings changed).

Note: No public exploit code is available; this is a conceptual demonstration.

Blue Team

Detection Steps:

1. Monitor for unusual AJAX requests to admin-ajax.php with action parameters related to Solace.
2. Check for unauthorized changes to plugin settings or user roles.
3. Review access logs for requests from unauthenticated users to sensitive endpoints.

Honeypot Setup:

• Deploy a decoy WordPress instance with the vulnerable plugin to capture attacker behavior.

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /wp-admin/admin-ajax.php with action=solace_* parameters from unauthenticated sources.
  • Unusual patterns in solace_settings or other plugin options being modified.

• File IOCs:

  • Modified wp_options table entries for solace_settings.
  • Unexpected files in /wp-content/plugins/solace/ directory.

• Log IOCs:

  • Repeated 200 responses to admin-ajax.php without prior authentication.
  • Error logs showing missing capability checks.

Detection Engineering

YARA Rule

rule CVE_2025_68911_Solace_Missing_Auth {
    meta:
        description = "Detects missing authorization in Solace WordPress plugin"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-68911"
    strings:
        $vuln_func = "add_action('wp_ajax_nopriv_" ascii wide
        $solace_prefix = "solace_" ascii wide
    condition:
        $vuln_func and $solace_prefix
}

Sigma Rule

title: CVE-2025-68911 - Solace Plugin Missing Authorization
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects exploitation attempts of missing authorization in Solace plugin
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=solace_'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin actions
level: medium

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2025-68911 - Solace Plugin Missing Authorization Attempt";
    flow:to_server;
    content:"POST";
    http_method;
    content:"admin-ajax.php";
    http_uri;
    content:"action=solace_";
    http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Solace plugin until a patch is released.
2. Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with action=solace_* from unauthenticated users.
3. Monitor logs for signs of exploitation.

Long-term Fix:

• Apply the vendor patch when available.
• Conduct a security audit of all WordPress plugins for similar authorization flaws.

Workaround:

• Add a custom capability check in the plugin's code (if you have developer access):

  add_action('wp_ajax_solace_action', 'solace_handle_action');
  

Valters IT