CVE-2023-51309 in Car Park Booking System
Summary
by MITRE • 02/20/2025
A lack of rate limiting in the 'Email Settings' feature of PHPJabbers Car Park Booking System v3.0 allows attackers to send an excessive amount of email for a legitimate user, leading to a possible Denial of Service (DoS) via a large amount of generated e-mail messages.
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Analysis
by VulDB Data Team • 03/07/2026
The vulnerability identified as CVE-2023-51309 resides within the Email Settings functionality of PHPJabbers Car Park Booking System version 3.0, representing a critical security flaw that directly impacts the system's availability and operational integrity. This weakness manifests as an insufficient rate limiting mechanism that governs the frequency and volume of email communications generated by the application's email configuration features. The absence of proper throttling controls enables malicious actors to exploit this functionality without restraint, potentially overwhelming the system's email infrastructure and compromising legitimate user services.
The technical implementation of this vulnerability stems from the application's failure to enforce any form of rate limiting or request validation on email sending operations within the Car Park Booking System. When legitimate users attempt to configure email notifications or receive automated messages related to parking reservations, the system processes these requests without monitoring or restricting the volume of outbound emails. This design flaw creates an environment where attackers can programmatically trigger massive email generation sequences, effectively transforming what should be a controlled service into a potential vector for resource exhaustion attacks. The vulnerability directly maps to CWE-770, which categorizes inadequate resource management and insufficient rate limiting as critical weaknesses that can lead to denial of service conditions.
From an operational perspective, this vulnerability poses significant risks to both system availability and resource consumption within the Car Park Booking System environment. Attackers can leverage this weakness to flood the email infrastructure with excessive messages, potentially exhausting bandwidth, storage capacity, and processing resources dedicated to email handling. The impact extends beyond simple email delivery disruption, as the system may become unresponsive to legitimate user requests, effectively creating a denial of service condition that affects the core functionality of the parking booking service. This vulnerability particularly threatens organizations that rely on automated email communications for reservation confirmations, notifications, and administrative alerts, as the malicious email flooding could render these critical services unavailable to genuine users.
The attack surface for this vulnerability encompasses any user with access to the Email Settings feature of the Car Park Booking System, including both administrative and regular user accounts that might be compromised or misused. Attackers can exploit this weakness through automated scripts or tools that repeatedly trigger email generation functions, potentially overwhelming the email server and causing cascading failures throughout the application's communication infrastructure. This threat model aligns with ATT&CK technique T1499.004, which describes resource exhaustion attacks targeting email services and messaging infrastructure. The vulnerability's exploitation requires minimal technical sophistication, making it particularly dangerous as it can be leveraged by threat actors with varying skill levels to disrupt service availability.
Mitigation strategies for CVE-2023-51309 should focus on implementing robust rate limiting controls within the Email Settings functionality, establishing configurable thresholds for email sending frequency and volume. Organizations should deploy monitoring systems to detect unusual email generation patterns and implement automated alerts for potential abuse scenarios. The system should enforce per-user or per-session email limits, track email sending rates, and implement temporary account lockouts or access restrictions when abnormal activity is detected. Additionally, administrators should consider implementing email queuing mechanisms with proper scheduling controls to prevent immediate burst processing of email requests. Security hardening measures should include regular vulnerability assessments, proper access controls for email configuration features, and implementation of intrusion detection systems to monitor for exploitation attempts. The solution must address the underlying rate limiting deficiency while maintaining legitimate user functionality and ensuring that the system can continue to provide essential email services to authorized users without disruption.