CVE-2014-7829 in Ruby on Rails
Summary
by MITRE
Directory traversal vulnerability in actionpack/lib/action_dispatch/middleware/static.rb in Action Pack in Ruby on Rails 3.x before 3.2.21, 4.0.x before 4.0.12, 4.1.x before 4.1.8, and 4.2.x before 4.2.0.beta4, when serve_static_assets is enabled, allows remote attackers to determine the existence of files outside the application root via vectors involving a \ (backslash) character, a similar issue to CVE-2014-7818.
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Analysis
by VulDB Data Team • 04/04/2022
The CVE-2014-7829 vulnerability represents a directory traversal flaw within the Action Pack component of Ruby on Rails web applications. This security issue specifically affects versions prior to the mentioned patches across multiple Rails release lines including 3.x, 4.0.x, 4.1.x, and 4.2.x. The vulnerability manifests when the serve_static_assets configuration is enabled, creating a pathway for remote attackers to probe the file system outside the intended application root directory. The flaw leverages the backslash character as a vector to manipulate file path resolution, enabling attackers to determine whether specific files exist beyond the application's designated boundaries.
The technical implementation of this vulnerability stems from inadequate input validation within the static file serving middleware. Action Pack's static.rb file fails to properly sanitize user-supplied paths when processing requests for static assets, allowing malicious input containing backslash characters to bypass normal path resolution mechanisms. This weakness specifically impacts how the framework handles file system navigation when static assets are served, creating an information disclosure condition where attackers can enumerate files and directories outside the application's intended scope. The vulnerability is classified under CWE-22 as a directory traversal attack, where improper input validation allows access to unintended resources.
The operational impact of CVE-2014-7829 extends beyond simple information disclosure to potentially enable more sophisticated attacks. While the primary effect allows attackers to determine file existence, this information can serve as a foundation for further exploitation including potential file content retrieval, system reconnaissance, and enumeration of sensitive files such as configuration files, database credentials, or application source code. The vulnerability affects applications that serve static assets directly through the Rails framework rather than through a reverse proxy or dedicated web server, making it particularly concerning for applications with complex static asset serving requirements. Security researchers have noted that this issue shares similarities with CVE-2014-7818, indicating a pattern of path traversal vulnerabilities within Rails' static asset handling mechanisms.
Organizations affected by this vulnerability should immediately implement mitigations including updating to patched versions of Ruby on Rails, disabling serve_static_assets when not required, or implementing proper input validation at the application level. The ATT&CK framework categorizes this as a reconnaissance technique where adversaries gather information about the target environment before launching more targeted attacks. Security teams should also consider implementing web application firewalls to detect and block suspicious path traversal patterns, particularly those involving backslash characters. Additionally, organizations should conduct comprehensive security assessments to identify all applications running vulnerable versions of Rails and ensure proper patch management procedures are in place to prevent similar issues in the future.