CVE-2006-0814 in Lighttpd
Summary
by MITRE
response.c in Lighttpd 1.4.10 and possibly previous versions, when run on Windows, allows remote attackers to read arbitrary source code via requests that contain trailing (1) "." (dot) and (2) space characters, which are ignored by Windows, as demonstrated by PHP files.
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Analysis
by VulDB Data Team • 07/08/2021
The vulnerability identified as CVE-2006-0814 represents a critical path traversal flaw in Lighttpd web server version 1.4.10 and earlier releases when operating on Windows platforms. This security issue stems from the server's improper handling of file path resolution, specifically when processing requests containing trailing dot and space characters. The flaw exploits fundamental differences in how Windows and Unix-like systems interpret file paths, creating a window for unauthorized code access that could potentially expose sensitive source code to remote attackers.
The technical implementation of this vulnerability occurs in the response.c component of Lighttpd's codebase where the server fails to properly sanitize or normalize file paths before processing them. When a malicious request contains trailing dot characters followed by space characters, Windows filesystem behavior ignores these characters during path resolution, allowing the server to traverse directories in unintended ways. This occurs because Windows treats the dot-space combination as equivalent to the current directory reference, while Lighttpd does not account for this Windows-specific behavior during path validation. The vulnerability specifically affects PHP files but could potentially impact any file type processed by the web server, making it particularly dangerous in environments where multiple file types are served.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the ability to access arbitrary source code files on the server filesystem. This could lead to exposure of application logic, database credentials, configuration files, and other sensitive information that might be stored in the same directory structure as the web-accessible content. The attack vector is particularly concerning because it requires minimal payload complexity - simply appending a dot and space to a request URL can bypass normal path restrictions. Security professionals should note that this vulnerability aligns with CWE-22 Path Traversal and CWE-77 Path Traversal, representing a classic case where operating system differences create security gaps in application design. The vulnerability also maps to ATT&CK technique T1083 File and Directory Discovery, as it enables attackers to enumerate and access files beyond the intended web root.
Mitigation strategies for this vulnerability should focus on immediate patching of Lighttpd installations to versions that properly handle path normalization on Windows systems. System administrators should implement strict input validation at the web server level, ensuring that all file path requests are normalized and validated against acceptable patterns before processing. Network-level protections such as web application firewalls can help detect and block malicious requests containing suspicious path sequences. Additionally, organizations should conduct comprehensive security audits of their web server configurations to identify any other potential path traversal vulnerabilities, particularly in environments where multiple operating systems are supported. The vulnerability demonstrates the critical importance of understanding platform-specific behaviors in web application security and highlights the necessity of thorough testing across different operating environments during security assessments.