CVE-2001-0463 in PerlCal
Summary
by MITRE
Directory traversal vulnerability in cal_make.pl in PerlCal allows remote attackers to read arbitrary files via a .. (dot dot) in the p0 parameter.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/01/2024
The vulnerability identified as CVE-2001-0463 represents a classic directory traversal flaw within the PerlCal calendar application's cal_make.pl script. This security weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied parameters before processing them within the application's file system operations. The vulnerability specifically manifests when the p0 parameter contains directory traversal sequences such as .. which allows attackers to navigate beyond the intended directory structure and access files that should remain restricted. The flaw operates at the application layer where user input directly influences file system access controls, creating an attack vector that can be exploited by remote adversaries without requiring authentication or privileged access.
This directory traversal vulnerability falls under the Common Weakness Enumeration category CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The attack technique aligns with the MITRE ATT&CK framework's technique T1083 - File and Directory Discovery, as it enables adversaries to enumerate and access arbitrary files on the target system. The vulnerability is particularly concerning because it allows attackers to bypass normal access controls and potentially read sensitive system files, configuration data, or other confidential information that should not be accessible through the web interface. The PerlCal application's failure to validate or sanitize the p0 parameter creates a direct pathway for malicious input to influence file system operations, making it a straightforward yet dangerous security flaw.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to access critical system resources including database files, configuration settings, application source code, and potentially even system credentials stored in accessible files. Remote exploitation of this vulnerability does not require specialized tools or deep technical knowledge, making it particularly dangerous for widespread abuse. The flaw affects the application's file handling mechanisms where user-provided path information is directly used to construct file system paths without proper validation or sanitization. This creates a persistent security risk that remains exploitable until the underlying input validation is properly implemented, potentially allowing attackers to gain unauthorized access to sensitive data and system resources that should be protected by normal access controls.
Mitigation strategies for CVE-2001-0463 should focus on implementing robust input validation and sanitization mechanisms within the cal_make.pl script. The most effective approach involves validating all user-supplied input parameters to ensure they contain only expected characters and do not include directory traversal sequences such as .. or similar path manipulation attempts. Implementing a whitelist approach that explicitly defines acceptable input patterns rather than attempting to blacklist dangerous characters proves most effective. Additionally, the application should employ proper path normalization techniques that resolve absolute paths and prevent traversal attacks by ensuring all file operations occur within designated safe directories. Organizations should also consider implementing proper access controls and privilege separation to limit the impact of any successful exploitation attempts, while regular security audits and code reviews should be conducted to identify and remediate similar vulnerabilities in other components of the application stack. The vulnerability demonstrates the critical importance of input validation in web applications and highlights the need for defensive programming practices that prevent malicious input from influencing system operations.