CVE-2005-1147 in CalendarScript
Summary
by MITRE
calendar.pl in CalendarScript 3.20 allows remote attackers to obtain sensitive information via invalid (1) calendar or (2) template parameters, which leaks the full pathname and debug information.
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Analysis
by VulDB Data Team • 07/22/2017
The vulnerability described in CVE-2005-1147 affects CalendarScript version 3.20 and specifically targets the calendar.pl script component. This issue represents a classic information disclosure vulnerability that occurs when the application fails to properly validate user input parameters. The flaw manifests when remote attackers submit malformed calendar or template parameters to the calendar.pl script, which then responds by revealing sensitive system information including full directory paths and debug output. Such vulnerabilities fall under the category of CWE-200 - Information Exposure, where the application inadvertently provides attackers with detailed system information that could be leveraged for further exploitation. The vulnerability directly impacts the principle of least privilege and information hiding that are fundamental to secure system design.
The technical implementation of this vulnerability stems from inadequate input validation and error handling within the CalendarScript application. When invalid calendar or template parameters are passed to the calendar.pl script, the application does not properly sanitize these inputs before processing them. Instead of gracefully handling the invalid input with a generic error message, the script reveals internal system details including the complete file path where the application is installed and debug information that should remain hidden from end users. This behavior violates security best practices and creates a significant information leakage scenario that can be exploited by threat actors to understand the target system's architecture and potentially identify additional attack vectors. The vulnerability demonstrates poor error handling practices that are commonly associated with weak input validation mechanisms.
From an operational impact perspective, this vulnerability enables remote attackers to gather critical system information that significantly reduces the attack surface for more sophisticated exploitation attempts. The leaked pathname information can reveal the exact installation directory structure of the CalendarScript application, potentially exposing the operating system type and file system layout. Debug information disclosure provides attackers with insights into the application's internal workings, including potential code paths and function names that could be targeted in subsequent attacks. This information disclosure vulnerability aligns with ATT&CK technique T1083 - File and Directory Discovery, as it allows adversaries to gather system information without requiring direct access to the target environment. The exposure of system paths can facilitate path traversal attacks or help attackers craft more effective payloads for other vulnerabilities that may exist within the same application.
Mitigation strategies for CVE-2005-1147 should focus on implementing proper input validation and error handling mechanisms within the CalendarScript application. The most effective approach involves sanitizing all user-supplied input parameters before processing them, ensuring that invalid inputs are rejected rather than processed and potentially exposing system information. Application developers should implement comprehensive error handling that prevents the disclosure of internal system details in error messages, adhering to the principle of minimal information disclosure. Organizations should also consider implementing proper logging and monitoring of unusual parameter inputs to detect potential exploitation attempts. Additionally, upgrading to a newer version of CalendarScript that addresses this vulnerability would provide the most reliable long-term solution. Security practitioners should also apply network-level controls such as firewalls and web application firewalls to limit access to the vulnerable script and reduce the attack surface. The remediation process should include thorough security testing to ensure that error handling has been properly implemented and that no additional information disclosure vulnerabilities exist within the application's codebase.