CVE-2003-1138 in HTTP Server
Summary
by MITRE
The default configuration of Apache 2.0.40, as shipped with Red Hat Linux 9.0, allows remote attackers to list directory contents, even if auto indexing is turned off and there is a default web page configured, via a GET request containing a double slash (//).
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Analysis
by VulDB Data Team • 07/20/2025
This vulnerability in Apache 2.0.40 represents a significant directory traversal issue that exploits a flaw in how the web server handles URL parsing with double slashes. The vulnerability stems from the default configuration shipped with Red Hat Linux 9.0 where Apache fails to properly sanitize incoming requests containing double slash sequences, allowing unauthorized access to directory listings despite security measures such as disabled auto-indexing and configured default web pages. The technical flaw occurs at the URL parsing layer where the web server interprets double slash sequences in a manner that bypasses normal access controls, effectively creating a path traversal condition that can be exploited by remote attackers. This issue directly relates to CWE-22 which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal vulnerabilities. The vulnerability operates through the HTTP GET request mechanism where attackers can manipulate URL paths to access directories that should normally be restricted.
The operational impact of this vulnerability is substantial as it allows remote attackers to enumerate directory contents on web servers running the affected Apache version, potentially exposing sensitive files, configuration data, or application source code. Attackers can leverage this weakness to gain intelligence about the server structure and identify potential targets for further exploitation. The vulnerability is particularly dangerous because it bypasses standard security controls such as directory indexing restrictions and default page configurations, making it difficult to detect and mitigate through conventional means. This type of vulnerability falls under ATT&CK technique T1213 which involves data from information repositories, as attackers can harvest information about the target environment through directory listing capabilities. The issue represents a configuration weakness that affects the fundamental security model of the web server, as it allows unauthorized access to files that should be protected by normal access controls.
The mitigation strategy for this vulnerability involves several approaches that address both the immediate security gap and prevent similar issues from occurring in the future. System administrators should immediately update to a patched version of Apache 2.0.40 or apply the appropriate security patches released by the Apache Software Foundation. Configuration hardening should include implementing proper URL sanitization rules and ensuring that the web server properly handles special characters in URL paths. The recommended approach includes disabling the problematic behavior through custom configuration directives that enforce proper path resolution and prevent double slash interpretation from bypassing access controls. Additionally, implementing web application firewalls or security modules such as mod_security can provide additional layers of protection by monitoring and filtering suspicious URL patterns. Organizations should also conduct comprehensive security audits to identify other potential configuration issues and ensure that all web server components are properly configured according to security best practices. This vulnerability underscores the importance of proper input validation and the need for robust security testing of web server configurations, particularly when dealing with default installations that may contain inherent security weaknesses.