CVE-2024-35672: Netgsm Authorization Bypass Vulnerability

CVE-2024-35672 Overview

CVE-2024-35672 is a Missing Authorization vulnerability affecting the Netgsm WordPress plugin. This vulnerability allows unauthenticated attackers to bypass access controls and interact with plugin functionality without proper authorization checks, potentially leading to unauthorized data access, modification, or complete site compromise.

Critical Impact

This vulnerability enables unauthenticated attackers to bypass authorization controls in the Netgsm WordPress plugin, potentially allowing complete compromise of confidentiality, integrity, and availability of the affected WordPress installation.

Affected Products

• Netgsm WordPress Plugin versions up to and including 2.9.19
• WordPress installations with the Netgsm plugin enabled
• Netgsm SMS and communication integrations utilizing the vulnerable plugin

Discovery Timeline

• 2024-06-04 - CVE-2024-35672 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-35672

Vulnerability Analysis

This vulnerability is classified as CWE-862 (Missing Authorization), which represents a critical security flaw where the application fails to perform authorization checks before allowing access to protected functionality or resources. In the context of the Netgsm WordPress plugin, the vulnerability allows attackers to access administrative or privileged functions without proper verification of user permissions.

The Netgsm plugin is designed to integrate SMS functionality with WordPress, enabling site administrators to send SMS notifications and messages. Without proper authorization controls, attackers can potentially manipulate SMS settings, access sensitive configuration data, or abuse the SMS sending functionality.

Root Cause

The root cause of CVE-2024-35672 is the absence of proper authorization checks (capability checks) in one or more plugin functions. WordPress plugins must verify that the current user has appropriate capabilities before executing privileged operations. The Netgsm plugin fails to implement these checks, allowing any user—including unauthenticated visitors—to invoke protected functionality.

This is a common issue in WordPress plugins where developers implement AJAX handlers or REST API endpoints without wrapping them in capability checks such as current_user_can() or without proper nonce verification.

Attack Vector

The vulnerability is exploitable over the network without requiring authentication or user interaction. An attacker can craft malicious requests directly to the vulnerable plugin endpoints. The attack scenario typically involves:

1. Identifying vulnerable AJAX actions or REST endpoints exposed by the Netgsm plugin
2. Crafting HTTP requests that invoke these endpoints without authentication
3. Exploiting the lack of authorization to access or modify protected resources
4. Potentially chaining with other vulnerabilities to achieve persistent access

Since the vulnerability requires no privileges and no user interaction, it can be exploited through automated scanning and attacks targeting WordPress installations with the Netgsm plugin installed.

Detection Methods for CVE-2024-35672

Indicators of Compromise

• Unexpected HTTP requests to Netgsm plugin AJAX endpoints from unauthenticated sources
• Unauthorized modifications to Netgsm plugin settings or configurations
• Suspicious SMS activity or configuration changes in the plugin dashboard
• Log entries showing access to administrative plugin functions without corresponding authenticated sessions
• Unusual traffic patterns to /wp-admin/admin-ajax.php with Netgsm-related actions

Detection Strategies

• Monitor WordPress access logs for requests to AJAX handlers associated with the Netgsm plugin from unauthenticated sources
• Implement Web Application Firewall (WAF) rules to detect and block exploitation attempts
• Deploy file integrity monitoring to detect unauthorized changes to plugin files or settings
• Utilize WordPress security plugins that can identify broken access control issues

Monitoring Recommendations

• Enable comprehensive logging for WordPress AJAX requests and REST API endpoints
• Configure alerting for changes to plugin settings outside of normal administrative activity
• Implement rate limiting on AJAX endpoints to prevent automated exploitation attempts
• Review audit logs regularly for unauthorized access patterns to the Netgsm plugin

How to Mitigate CVE-2024-35672

Immediate Actions Required

• Update the Netgsm WordPress plugin to a patched version beyond 2.9.19 if available
• If no patch is available, deactivate and remove the Netgsm plugin until a fix is released
• Review WordPress audit logs for any signs of exploitation
• Verify that no unauthorized changes have been made to plugin settings or site configuration
• Consider implementing additional access controls at the web server level to restrict access to AJAX endpoints

Patch Information

This vulnerability affects Netgsm plugin versions from the initial release through 2.9.19. Users should check for updates through the WordPress plugin repository or consult the Patchstack vulnerability database for the latest patch availability and remediation guidance.

Workarounds

• Temporarily deactivate the Netgsm plugin until a patched version is available
• Implement WAF rules to block unauthenticated requests to Netgsm-specific AJAX actions
• Restrict access to admin-ajax.php for unauthenticated users where feasible
• Use WordPress security plugins to add virtual patching capabilities
• Consider alternative SMS integration plugins that have proper authorization controls

# Example: Block Netgsm AJAX requests from unauthenticated users via .htaccess
# Add to WordPress root .htaccess file
<Files admin-ajax.php>
    <If "%{QUERY_STRING} =~ /action=netgsm/">
        Require all denied
    </If>
</Files>