CVE-2006-6279 in Alex Guestbook
Summary
by MITRE
index.php in @lex Guestbook 4.0.1 allows remote attackers to obtain sensitive information via a skin parameter referencing a nonexistent skin, which reveals the installation path in an error message.
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Analysis
by VulDB Data Team • 10/03/2017
The vulnerability described in CVE-2006-6279 affects @lex Guestbook version 4.0.1 and represents a classic information disclosure flaw that can be exploited by remote attackers to gain insights into the system's file structure. This vulnerability specifically manifests in the index.php script where the application fails to properly validate user input parameters, particularly the skin parameter that controls the guestbook's visual presentation. When an attacker provides a skin parameter referencing a nonexistent skin file, the application generates an error message that inadvertently exposes the full server path where the application is installed, creating a significant security risk.
The technical flaw stems from inadequate error handling and input validation mechanisms within the guestbook application's codebase. The system does not properly sanitize or validate the skin parameter before attempting to process it, allowing malicious users to inject arbitrary values that trigger error conditions. This particular vulnerability falls under the CWE-200 category of "Information Exposure" and demonstrates poor secure coding practices where error messages contain sensitive system information. The error message reveals the complete installation path including directory structure, which can be leveraged by attackers to understand the server environment and potentially identify other vulnerabilities or attack vectors.
From an operational impact perspective, this vulnerability creates a substantial risk for organizations deploying the affected software. The exposure of installation paths enables attackers to conduct more sophisticated attacks by understanding the application's file structure and potentially identifying other files or directories that might be accessible. This information disclosure can serve as a foundation for further exploitation attempts, including directory traversal attacks, local file inclusion vulnerabilities, or simply providing attackers with better understanding of the target environment. The vulnerability is particularly concerning because it requires minimal effort to exploit and provides attackers with actionable intelligence about the system's configuration.
The attack pattern associated with this vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1068 (Exploitation for Privilege Escalation) where attackers can use information disclosure to gather intelligence for more advanced attacks. Organizations should implement proper error handling mechanisms that do not expose system paths or internal configuration details in error messages. The recommended mitigations include implementing input validation for all user-supplied parameters, sanitizing error messages to remove sensitive information, and configuring the application to display generic error messages to users while logging detailed technical information only in secure administrative logs. Additionally, regular security audits and code reviews should be conducted to identify similar issues in legacy applications, and the affected software should be updated to a patched version or replaced with a more secure alternative to prevent exploitation attempts.