CVE-2005-3910 in Post Affiliate Pro
Summary
by MITRE
merchants/index.php in Post Affiliate Pro 2.0.4 and earlier, with magic_quotes_gpc disabled, allows remote attackers to include arbitrary local files via the md parameter, possibly due to a directory traversal vulnerability.
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Analysis
by VulDB Data Team • 07/26/2017
The vulnerability described in CVE-2005-3910 represents a critical directory traversal flaw in Post Affiliate Pro version 2.0.4 and earlier installations. This issue specifically affects the merchants/index.php script where the md parameter is processed without proper input validation or sanitization. The vulnerability becomes exploitable when the PHP configuration has magic_quotes_gpc disabled, which removes the automatic escaping of special characters that would otherwise prevent malicious input from being interpreted as file system commands. This creates a dangerous condition where remote attackers can manipulate the md parameter to traverse directories and include arbitrary local files on the server.
The technical implementation of this vulnerability stems from improper input handling within the application's file inclusion mechanism. When the md parameter is passed to the merchants/index.php script, the application directly incorporates this user-supplied input into file system operations without adequate validation or sanitization. This allows attackers to craft malicious input strings that can navigate through the file system hierarchy using directory traversal sequences such as ../ or ../../../. The vulnerability is particularly severe because it enables arbitrary file inclusion, which can lead to unauthorized access to sensitive system files, configuration data, or even allow attackers to execute arbitrary code on the affected server. This type of vulnerability is categorized under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", which is a well-documented weakness in web application security.
The operational impact of this vulnerability extends far beyond simple information disclosure. Attackers can leverage this weakness to access critical system files, potentially including database configuration files, application source code, or server configuration details. The remote exploitation capability means that attackers do not need physical access to the system or local network connectivity to exploit this vulnerability. This makes it particularly dangerous in web-facing applications where the attack surface is maximized. The vulnerability also aligns with several techniques documented in the MITRE ATT&CK framework under the T1059 category for Command and Scripting Interpreter, as successful exploitation could enable attackers to execute arbitrary commands on the compromised system. Furthermore, this vulnerability could be used as a stepping stone for more sophisticated attacks, potentially leading to full system compromise or lateral movement within the network infrastructure.
Mitigation strategies for this vulnerability must address both the immediate security flaw and the underlying configuration issues that make it exploitable. The primary fix involves implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in file system operations. Developers should employ whitelisting techniques to restrict acceptable values for the md parameter or implement strict path validation that prevents directory traversal sequences from being processed. The application should also validate that any file inclusion operations occur within a predetermined safe directory structure and reject any attempts to access files outside of this designated scope. Additionally, system administrators should ensure that magic_quotes_gpc is enabled or implement equivalent input sanitization measures at the application level. Regular security updates and patches should be applied to ensure that the application remains protected against known vulnerabilities. Organizations should also implement proper network segmentation and monitoring to detect and prevent exploitation attempts, as this vulnerability could be part of a broader attack pattern targeting web applications. The remediation process should include comprehensive code review to identify similar vulnerabilities in other parts of the application and ensure that proper input validation is implemented consistently throughout the codebase.