CVE-2000-0432 in Calendar Script
Summary
by MITRE
The calender.pl and the calendar_admin.pl calendar scripts by Matt Kruse allow remote attackers to execute arbitrary commands via shell metacharacters.
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Analysis
by VulDB Data Team • 10/15/2025
The vulnerability identified as CVE-2000-0432 represents a critical command injection flaw in the Matt Kruse calendar scripts, specifically affecting both calender.pl and calendar_admin.pl applications. This issue stems from insufficient input validation and sanitization within the calendar management software, creating an avenue for remote attackers to execute arbitrary system commands on the affected server. The vulnerability manifests through the improper handling of user-supplied data that gets directly incorporated into shell commands without adequate filtering or escaping mechanisms. Attackers can exploit this weakness by injecting shell metacharacters such as semicolons, ampersands, or backticks into input fields that are processed by these scripts, thereby gaining unauthorized access to the underlying operating system.
The technical exploitation of this vulnerability aligns with CWE-77 which categorizes improper neutralization of special elements used in a command, and specifically relates to CWE-94 which deals with the execution of code in a context that allows arbitrary code execution. This flaw operates at the intersection of multiple attack vectors defined in the MITRE ATT&CK framework, particularly under the execution tactics where adversaries can leverage command injection to run malicious code on compromised systems. The vulnerability exists in the application layer of the network stack, making it particularly dangerous as it can be exploited remotely without requiring authentication or physical access to the system. The affected scripts likely process user input through web forms or API endpoints that directly feed into system shell commands, creating a direct pathway for privilege escalation and system compromise.
The operational impact of this vulnerability is severe and multifaceted, potentially allowing attackers to execute commands with the privileges of the web server process, which typically runs with elevated permissions on the target system. Successful exploitation could lead to complete system compromise, data exfiltration, lateral movement within the network, and establishment of persistent backdoors. The calendar scripts, being web-accessible applications, provide attackers with a readily available attack surface that can be leveraged for reconnaissance, privilege escalation, and further exploitation of the network infrastructure. Organizations running these vulnerable scripts face significant risk of unauthorized access, data breaches, and potential regulatory compliance violations. The vulnerability also affects the availability and integrity of the calendar services, as attackers could potentially disrupt the functionality of the calendar applications or corrupt stored data.
Mitigation strategies for this vulnerability should focus on immediate input validation and sanitization measures, including the implementation of proper escape sequences and parameterized input handling for all user-supplied data. Organizations should apply the latest security patches provided by the vendor or migrate to more secure calendar solutions that properly handle user input. Network segmentation and access controls should be implemented to limit exposure of these vulnerable applications to untrusted networks. Regular security auditing and code reviews should be conducted to identify similar input validation flaws in other applications. Additionally, implementing web application firewalls and intrusion detection systems can help detect and prevent exploitation attempts. The vulnerability highlights the critical importance of secure coding practices and input validation, particularly in applications that interact with system-level commands, and serves as a reminder of the need for comprehensive security testing throughout the software development lifecycle.