CVE-2004-2343 in HTTP Server
Summary
by MITRE
** disputed ** apache http server 2.0.47 and earlier allows local users to bypass .htaccess file restrictions as specified in httpd.conf with directives such as deny from all by using an errordocument directive. note: the vendor has disputed this issue since the .htaccess mechanism is only intended to restrict external web access and a local user already has the privileges to perform the same operations without using errordocument.
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Analysis
by VulDB Data Team • 08/08/2024
The vulnerability described in CVE-2004-2343 pertains to a security flaw in the Apache HTTP Server version 2.0.47 and earlier, where local users can potentially bypass restrictions imposed by .htaccess files through strategic use of the errordocument directive within the main httpd.conf configuration file. This issue arises from a fundamental misunderstanding of how Apache's access control mechanisms should function in relation to local versus external access privileges. The flaw demonstrates a critical gap in the server's authorization model, where the intended security boundary between external and internal access is circumvented by a local user who can manipulate error handling configurations to gain unauthorized access to resources that should remain restricted.
The technical implementation of this vulnerability involves the interaction between Apache's configuration hierarchy where .htaccess files operate at the directory level to control access for external clients, while the main httpd.conf file contains global server directives including error document handling. When an errordocument directive is used in the main configuration, it can override or extend the access controls established by .htaccess files, creating a scenario where local users can manipulate the server's error handling behavior to bypass the intended access restrictions. This represents a violation of the principle of least privilege and demonstrates how error handling configurations can inadvertently create security loopholes when not properly coordinated with access control mechanisms.
From an operational perspective, this vulnerability poses significant risks to systems where local users have access to the server environment but should not be able to bypass directory-level access controls established through .htaccess files. The impact extends beyond simple privilege escalation as it undermines the entire access control architecture that relies on the separation between external and internal access points. This flaw could enable local users to access restricted directories, files, or resources that should only be accessible to authorized external clients, effectively nullifying the security measures that administrators implement through .htaccess configurations.
The vendor's disputed classification of this issue stems from their argument that .htaccess files are specifically designed to control external web access and that local users should already possess the necessary privileges to perform operations without relying on the web server's access control mechanisms. However, this perspective fails to acknowledge that administrators might legitimately expect access restrictions to function consistently regardless of whether access is internal or external, and that the security model should prevent unauthorized access even when local users have elevated system privileges. This vulnerability aligns with CWE-284, which addresses improper access control, and reflects the broader category of privilege escalation issues that can occur when security boundaries are improperly enforced.
Organizations should implement mitigations that focus on proper configuration management and access control enforcement, ensuring that error document configurations do not inadvertently bypass directory-level restrictions. The recommended approach involves reviewing and properly securing the httpd.conf file to prevent local users from manipulating error handling behaviors that could compromise access controls, while also ensuring that .htaccess files and main configuration files work cohesively to maintain consistent security policies. This vulnerability serves as a reminder of the importance of comprehensive security testing that examines interactions between different configuration layers and access control mechanisms, particularly in complex web server environments where multiple security controls must work in harmony to maintain effective protection against both external and internal threats.