CVE-2023-24373 in Booking Calendar, Appointment Booking System Plugin
Summary
by MITRE • 06/04/2024
External Control of Assumed-Immutable Web Parameter vulnerability in WpDevArt Booking calendar, Appointment Booking System allows Manipulating Hidden Fields.This issue affects Booking calendar, Appointment Booking System: from n/a through 3.2.3.
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Analysis
by VulDB Data Team • 03/21/2025
The CVE-2023-24373 vulnerability represents a critical security flaw in the WpDevArt Booking calendar and Appointment Booking System plugin, specifically targeting the improper handling of web parameters that should remain immutable. This vulnerability falls under the category of external control of assumed-immutable web parameters, a weakness that directly violates fundamental security principles of input validation and parameter integrity. The flaw manifests when the system fails to properly validate or sanitize hidden form fields that are expected to remain unchanged during user interaction, creating an attack surface where malicious actors can manipulate booking parameters through crafted requests.
The technical implementation of this vulnerability stems from the plugin's failure to enforce proper validation controls on hidden input fields that contain critical booking data such as dates, times, resource allocations, and pricing information. When users interact with the booking interface, the system generates hidden form fields to maintain state and preserve booking parameters. However, due to insufficient server-side validation, these fields can be modified by attackers who intercept and alter the HTTP requests before submission. This weakness directly maps to CWE-471, which addresses the vulnerability of data being modified in a way that should be immutable, and also aligns with CWE-20, which covers improper input validation. The attack vector typically involves intercepting form data through man-in-the-middle techniques or direct request manipulation, allowing adversaries to bypass normal booking restrictions and potentially manipulate booking outcomes.
The operational impact of this vulnerability extends beyond simple parameter manipulation, creating potential risks for businesses relying on the booking system for appointment scheduling and resource management. Attackers could exploit this flaw to book appointments outside of normal business hours, manipulate pricing structures, or gain unauthorized access to restricted booking slots. The vulnerability particularly affects organizations that depend on accurate booking data for resource allocation, staff scheduling, and revenue management. From an attacker's perspective, this represents a low-effort, high-impact vector that can be automated through scripting tools, potentially enabling large-scale booking manipulation across multiple calendar entries. The security implications also extend to potential data integrity issues that could compromise the reliability of booking records and create audit trail inconsistencies.
Mitigation strategies for CVE-2023-24373 require immediate implementation of robust server-side validation mechanisms that treat all form parameters as potentially malicious until proven otherwise. Organizations should implement strict input sanitization and validation routines that verify the integrity of hidden form fields against expected values, implementing cryptographic signatures or checksums to detect unauthorized modifications. The recommended approach includes enforcing proper parameter validation using secure coding practices that align with OWASP Top Ten security guidelines, particularly focusing on input validation and data integrity controls. Additionally, implementing request origin verification and session-based token validation can significantly reduce the attack surface. Security teams should also consider implementing rate limiting and monitoring mechanisms to detect unusual booking patterns that might indicate exploitation attempts. The vulnerability's classification under ATT&CK technique T1213.002, which addresses data from information repositories, underscores the need for comprehensive access controls and audit logging to track parameter modifications and maintain system integrity. Organizations should prioritize patching the affected versions through official updates and implement network-level protections such as web application firewalls to prevent exploitation attempts.