CVE-2015-3675 in Mac OS X
Summary
by MITRE
The default configuration of the Apache HTTP Server on Apple OS X before 10.10.4 does not enable the mod_hfs_apple module, which allows remote attackers to bypass HTTP authentication via a crafted URL.
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Analysis
by VulDB Data Team • 05/22/2022
The vulnerability identified as CVE-2015-3675 represents a significant security flaw in the default Apache HTTP Server configuration on Apple macOS systems prior to version 10.10.4. This issue stems from the absence of the mod_hfs_apple module being enabled by default, creating an exploitable condition that affects the server's ability to properly handle HTTP authentication mechanisms. The flaw specifically targets the interaction between Apache's authentication system and the HFS+ filesystem handling capabilities that Apple introduced for their operating systems.
The technical root cause of this vulnerability lies in the missing mod_hfs_apple module which is responsible for proper handling of HFS+ filesystem paths and authentication requirements when serving content from Apple's native filesystem. When this module is not enabled, the Apache server fails to properly validate and enforce authentication requirements for certain URL patterns that contain specific path structures. Attackers can exploit this by crafting malicious URLs that bypass the standard authentication checks, allowing unauthorized access to protected resources that should otherwise require valid credentials.
This vulnerability operates at the application layer of the network stack and represents a configuration-based weakness rather than a fundamental flaw in the HTTP protocol itself. The operational impact extends beyond simple unauthorized access to potentially sensitive data, as attackers can leverage this bypass to gain access to restricted directories, files, and resources that are protected by HTTP authentication mechanisms. The vulnerability affects all Apple macOS versions before 10.10.4, making it particularly concerning given the widespread deployment of these systems in enterprise and organizational environments.
The security implications of CVE-2015-3675 align with CWE-284, which addresses improper access control vulnerabilities, and can be categorized under ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting through social engineering or exploitation of system misconfigurations. The flaw demonstrates how default security configurations can create dangerous gaps in protection, particularly when system administrators rely on vendor defaults without proper security hardening. This vulnerability essentially creates a backdoor path that allows attackers to bypass authentication controls that are typically enforced by the web server, potentially leading to complete system compromise if sensitive resources are accessible through the affected paths.
Organizations affected by this vulnerability should immediately implement the necessary security patches provided by Apple, ensuring that the mod_hfs_apple module is properly enabled in the Apache configuration. System administrators should also conduct comprehensive security audits to verify that all default configurations align with security best practices, particularly focusing on authentication enforcement mechanisms. Additional mitigations include implementing network-level access controls, monitoring for suspicious URL patterns, and ensuring that all web server configurations undergo regular security reviews to prevent similar misconfigurations from occurring in other components or services. The vulnerability underscores the critical importance of proper security configuration management and the potential for seemingly minor configuration omissions to create significant security risks in enterprise environments.