CVE-2005-0998 in PHP-Nuke
Summary
by MITRE
The Web_Links module for PHP-Nuke 7.6 allows remote attackers to obtain sensitive information via an invalid show parameter, which triggers a division by zero PHP error that leaks the full pathname of the server.
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Analysis
by VulDB Data Team • 07/07/2018
The vulnerability described in CVE-2005-0998 represents a classic information disclosure flaw within the Web_Links module of PHP-Nuke version 7.6. This issue arises from inadequate input validation mechanisms that fail to properly handle malformed parameters submitted to the application. The vulnerability specifically targets the show parameter within the Web_Links module, which when manipulated with invalid input values, triggers a critical division by zero error in the PHP runtime environment. This error condition creates a scenario where the underlying system information becomes exposed to remote attackers through error message generation.
The technical exploitation of this vulnerability demonstrates a fundamental flaw in error handling and parameter validation within the PHP-Nuke framework. When an attacker submits an invalid show parameter value, the application's code path leads to a mathematical operation attempting to divide by zero, which PHP handles by generating an error message. However, in this specific implementation, the error message includes the full server pathname in its output, effectively leaking sensitive system information to unauthorized parties. This type of information disclosure vulnerability falls under the CWE-200 category for "Information Exposure" and specifically relates to CWE-1243 which addresses "Error Message Information Exposure" through improper handling of division by zero conditions.
The operational impact of this vulnerability extends beyond simple information leakage, as the disclosed server path information can serve as a foundation for more sophisticated attacks. Attackers can leverage the leaked path information to construct targeted attacks against specific system directories, potentially leading to directory traversal exploits, file inclusion vulnerabilities, or other path-based attacks. The exposure of the full server pathname creates a significant risk for attackers seeking to understand the system architecture and locate sensitive files or directories that may contain additional vulnerabilities. This vulnerability aligns with ATT&CK technique T1083 for "File and Directory Discovery" and T1068 for "Exploitation for Privilege Escalation" as the leaked information can be used to craft more effective exploitation strategies.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and error handling mechanisms within the Web_Links module. The primary fix involves sanitizing all user-supplied parameters, particularly the show parameter, to ensure they conform to expected value ranges and types before processing. Additionally, the application should implement proper error handling that prevents sensitive system information from being exposed in error messages. This includes configuring PHP to suppress detailed error information in production environments and implementing custom error handlers that provide generic error responses to users while logging detailed information internally. The vulnerability also highlights the importance of regular security audits and input validation testing as recommended by OWASP Top 10 security practices. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability pattern.