CVE-2009-0843 in MapServer
Summary
by MITRE
The msLoadQuery function in mapserv in MapServer 4.x before 4.10.4 and 5.x before 5.2.2 allows remote attackers to determine the existence of arbitrary files via a full pathname in the queryfile parameter, which triggers different error messages depending on whether this pathname exists.
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Analysis
by VulDB Data Team • 08/31/2019
The vulnerability identified as CVE-2009-0843 affects MapServer versions 4.x prior to 4.10.4 and 5.x prior to 5.2.2, specifically within the msLoadQuery function in the mapserv component. This represents a classic information disclosure vulnerability that arises from improper error handling mechanisms within the software's file access validation processes. The flaw enables remote attackers to perform reconnaissance activities by exploiting the application's differential error messaging behavior when processing file paths.
The technical implementation of this vulnerability stems from the msLoadQuery function's inadequate validation of the queryfile parameter. When a full pathname is provided through this parameter, the function processes the request without sufficient sanitization or access control checks. The system generates distinct error messages based on whether the specified file path exists within the filesystem, creating a side-channel information leak. This behavior directly violates security principles of least privilege and proper input validation, as the application inadvertently reveals file system structure information to unauthorized users.
From an operational impact perspective, this vulnerability enables attackers to perform file system reconnaissance and enumeration attacks. By systematically testing various file paths, adversaries can map the underlying file system structure and identify the existence of sensitive files, directories, or system components. The vulnerability falls under CWE-200, Information Exposure, and aligns with ATT&CK technique T1213.002 for Credential Access - Credentials in Files. This capability significantly increases the attack surface for potential exploitation, as successful reconnaissance can lead to more sophisticated attacks such as path traversal, privilege escalation, or information gathering for further exploitation.
The security implications extend beyond simple file existence detection, as this vulnerability can be leveraged as a reconnaissance primitive in broader attack chains. Attackers can use the information gathered to identify system configuration files, database connection details, or other sensitive artifacts that may be present on the target system. The vulnerability demonstrates poor error handling practices and highlights the importance of implementing consistent error messaging that does not reveal system-specific information. Organizations should consider this issue in the context of defense in depth strategies, as it represents a fundamental security weakness in the application's input validation and error handling mechanisms.
Mitigation strategies should focus on implementing proper input validation and sanitization of the queryfile parameter to prevent path traversal attacks. The recommended approach includes implementing strict file path validation that rejects absolute paths and ensures proper directory traversal controls are in place. Additionally, error messages should be standardized to prevent information disclosure while maintaining operational utility for legitimate system administrators. The vulnerability underscores the critical importance of secure coding practices, particularly in web applications that process user-supplied input, and emphasizes the need for comprehensive security testing including penetration testing and code review processes to identify similar weaknesses in other components.