CVE-2016-1776 in OS X Server
Summary
by MITRE
Web Server in Apple OS X Server before 5.1 does not properly restrict access to .DS_Store and .htaccess files, which allows remote attackers to obtain sensitive configuration information via an HTTP request.
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Analysis
by VulDB Data Team • 07/10/2022
The vulnerability identified as CVE-2016-1776 represents a critical access control flaw within Apple's OS X Server web server implementation. This issue affects versions prior to 5.1 and stems from inadequate restrictions on sensitive file access within the web server's directory structure. The vulnerability specifically targets two critical file types that are commonly present in web server environments and contain sensitive configuration data. The .DS_Store files are macOS metadata files that store directory attributes and are typically created automatically by the operating system, while .htaccess files contain per-directory configuration directives for apache web servers. Both file types can potentially expose sensitive system information when accessed directly through HTTP requests.
The technical exploitation of this vulnerability occurs through simple HTTP requests that target these specific file types within the web server's accessible directories. When an attacker crafts an HTTP request to access .DS_Store or .htaccess files, the server fails to properly enforce access controls that should prevent unauthorized access to these configuration files. This flaw allows remote attackers to retrieve sensitive information that could include directory structures, server configuration parameters, and potentially authentication credentials or other system details. The vulnerability operates at the application layer of the network stack and leverages the web server's default file serving behavior without proper access restriction enforcement. This issue falls under the CWE-284 access control weakness category, specifically addressing improper access control mechanisms in web server implementations.
The operational impact of this vulnerability extends beyond simple information disclosure, as the sensitive configuration information obtained through these files can enable more sophisticated attacks. Attackers who successfully exploit this vulnerability can gain insights into the server's directory structure, potentially identifying other accessible resources or vulnerable components within the system. The .htaccess files, in particular, may contain authentication settings, security directives, or other configuration elements that could be leveraged to escalate privileges or identify additional attack vectors. Furthermore, .DS_Store files can reveal detailed directory listings and metadata that might expose sensitive organizational structures or file naming conventions. This information disclosure can significantly aid attackers in planning more targeted attacks against the affected system. The vulnerability aligns with several ATT&CK techniques including T1083 (File and Directory Discovery) and T1592 (Gather Victim Host Information) as it enables adversaries to collect system information through direct web access.
The mitigation strategy for CVE-2016-1776 involves updating to Apple OS X Server version 5.1 or later, which includes proper access control restrictions for these sensitive file types. System administrators should also implement additional protective measures such as configuring web server access controls to explicitly deny access to .DS_Store and .htaccess files through server configuration directives. Network segmentation and firewall rules can provide additional layers of protection by limiting access to the web server from untrusted networks. Regular security auditing of web server configurations should be conducted to ensure that sensitive files remain properly protected. Organizations should also implement monitoring solutions to detect unauthorized access attempts to these specific file types. The vulnerability demonstrates the importance of proper file access control implementation in web server environments and highlights the need for comprehensive security testing of server configurations. Security teams should also consider implementing automated scanning tools that can detect the presence of these vulnerable files in web server directories and alert administrators to potential exposure risks.