CVE-2002-0304 in Lil HTTP Server
Summary
by MITRE
Lil HTTP Server 2.1 allows remote attackers to read password-protected files via a /./ in the HTTP request.
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Analysis
by VulDB Data Team • 09/20/2025
The vulnerability described in CVE-2002-0304 affects Lil HTTP Server version 2.1 and represents a directory traversal flaw that enables remote attackers to bypass authentication mechanisms and access password-protected files. This issue stems from inadequate input validation within the HTTP request processing logic, specifically failing to properly sanitize or normalize path references that contain the sequence "/./" which is a common technique for navigating file system paths. The vulnerability operates by exploiting how the server interprets path components that include the current directory reference, allowing malicious actors to manipulate request paths and gain unauthorized access to restricted resources. The flaw directly impacts the server's ability to enforce access controls and maintain file system boundaries, creating a significant security risk for any system relying on this software for web serving operations.
This vulnerability is classified as a directory traversal attack pattern that aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The specific implementation flaw in Lil HTTP Server 2.1 demonstrates how insufficient input sanitization can lead to privilege escalation and information disclosure. The attack vector involves sending HTTP requests containing the "/./" sequence in the requested path, which the server fails to properly resolve or normalize, allowing the attacker to navigate to parent directories and access files that should remain protected. This type of vulnerability falls under the broader category of file system access control bypasses and represents a fundamental breakdown in the server's security model for handling file system operations.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can potentially lead to complete system compromise if sensitive configuration files, database credentials, or application source code are accessible through the traversal mechanism. Attackers can leverage this flaw to obtain administrative credentials, system configuration details, or application source code that could reveal additional vulnerabilities within the system. The remote nature of the attack means that an attacker does not require local system access or physical presence, making the vulnerability particularly dangerous for web servers exposed to the internet. Organizations using Lil HTTP Server 2.1 are at risk of data breaches, intellectual property theft, and potential system compromise, especially if the server hosts sensitive information or serves as a gateway to internal network resources.
Mitigation strategies for this vulnerability require immediate action including patching the server software to properly normalize and validate path components in HTTP requests, implementing proper input sanitization routines, and ensuring that all path references are properly resolved before file system access is granted. System administrators should also consider implementing web application firewalls that can detect and block suspicious path traversal patterns, including sequences like "/./", "../", and other malformed path components. The remediation process should include thorough testing to ensure that path normalization works correctly and that legitimate file access continues to function while preventing malicious traversal attempts. Additionally, organizations should conduct comprehensive security audits of their web server configurations, implement proper access controls, and establish monitoring systems to detect potential exploitation attempts. This vulnerability highlights the critical importance of input validation and proper path handling in web server implementations and serves as a reminder of the need for robust security practices in all components of web infrastructure. The issue also aligns with ATT&CK technique T1059 which involves command and script injection, as the ability to access protected files can enable further exploitation and privilege escalation activities.