CVE-2007-0609 in Advanced Guestbook
Summary
by MITRE
Directory traversal vulnerability in Advanced Guestbook 2.4.2 allows remote attackers to bypass .htaccess settings, and execute arbitrary PHP local files or read arbitrary local templates, via a .. (dot dot) in a lang cookie, followed by a filename without its .php extension, as demonstrated via a request to index.php.
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Analysis
by VulDB Data Team • 05/26/2025
The vulnerability described in CVE-2007-0609 represents a critical directory traversal flaw within Advanced Guestbook version 2.4.2, a widely deployed web application for managing guest comments and entries. This vulnerability specifically targets the application's handling of language cookie parameters and demonstrates how improper input validation can lead to severe security compromises. The flaw exists in the application's core logic where user-supplied cookie values are processed without adequate sanitization or validation, creating an exploitable path for malicious actors to access unauthorized system resources.
The technical implementation of this vulnerability exploits the lack of proper path validation in the guestbook's language selection mechanism. When attackers manipulate the lang cookie parameter to include directory traversal sequences such as ..%2F or similar encoded variants, the application fails to properly sanitize these inputs before using them to construct file paths. This allows the attacker to navigate outside the intended directory structure and access files that should remain protected by .htaccess restrictions. The vulnerability specifically affects the index.php file which serves as the primary entry point for the application's functionality, making it particularly dangerous as it provides access to the core application logic.
The operational impact of this vulnerability extends beyond simple file disclosure, as it enables remote attackers to execute arbitrary PHP code through local file inclusion techniques. By crafting malicious lang cookie values that point to template files or other PHP components, attackers can potentially execute code on the web server with the privileges of the web application. This represents a significant escalation from simple information disclosure to full remote code execution capabilities, as the attacker can leverage the directory traversal to bypass standard access controls and .htaccess protections that normally restrict direct file access. The vulnerability's exploitation demonstrates a clear path to privilege escalation and system compromise.
The security implications of this vulnerability align with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This classification encompasses the fundamental flaw where applications fail to properly validate user-supplied input before using it in file system operations. The vulnerability also maps to ATT&CK technique T1059.007 for Windows systems and T1059.008 for Unix systems, which covers execution through script interpreters, as the exploitation can lead to arbitrary code execution. Additionally, the vulnerability demonstrates characteristics of T1566, which involves the exploitation of vulnerabilities in web applications to gain unauthorized access to systems.
Mitigation strategies for this vulnerability require immediate implementation of input validation and sanitization measures within the application's cookie handling logic. The most effective approach involves implementing strict path validation that rejects any input containing directory traversal sequences or special characters that could enable path manipulation. Organizations should also consider implementing proper access controls that prevent direct file access through web interfaces, ensuring that all file operations occur through properly validated application interfaces. Additionally, the application should be updated to a newer version that addresses this vulnerability, as Advanced Guestbook 2.4.2 is an outdated version that likely contains additional unpatched security flaws. Regular security assessments and input validation testing should be implemented to prevent similar vulnerabilities from emerging in other application components, particularly in legacy systems that may not have received adequate security updates over time.