External risk intelligence

Ruby on Rails File Reading Vulnerability

CVE advisoryKnown Exploit

CVE-2016-0752

A directory traversal vulnerability in Ruby on Rails allows remote attackers to read arbitrary files by exploiting the render method. This impacts organizations using affected Ruby on Rails versions, potentially exposing sensitive data and posing a business risk.

4Halo Surface Signal

Path Traversal

Rubyonrails Rails

before 3.2.22.14.0.0 to before 4.1.14.14.2.0 to before 4.2.5.15.0.042.113.2128.01.0

External exposure likelihood

Halo Surface Signal score for CVE-2016-0752

This vulnerability affects the Action View component of Ruby on Rails, a widely used web application framework. Applications built with Rails are commonly deployed as public-facing web services or APIs. While exposure depends on the specific implementation of the render method, the framework itself is standard for internet-facing web applications.

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability exists within the Action View component of Ruby on Rails, a software framework used for building applications. The flaw allows unauthorized remote access to sensitive files on the system. This could lead to significant business risk if confidential or proprietary data is exposed.

Vulnerable: Ruby on Rails Action View
Flaw: Allows reading arbitrary files
Impact: Exposure of sensitive business data

Attack Path

How an attacker could exploit the issue

This vulnerability allows attackers to access arbitrary files on a system. Organizations using affected versions of Ruby on Rails may be at risk if their applications use the render method without proper safeguards. An attacker could exploit this by sending specially crafted input to an application, potentially leading to the disclosure of sensitive information.

Application renders user-supplied pathnames.
Attacker provides a dot-dot path.
Attacker reads arbitrary files.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability allows remote attackers to access arbitrary files on a system. Exploitation involves an application's unmonitored use of the render method combined with specially crafted pathnames. The potential impact includes unauthorized disclosure of sensitive information, posing a significant business risk.

Attackers likely need moderate skill.
Requires unpatched applications and specific coding.
Business risk is high; treat as urgent.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

Directory traversal vulnerabilities in Action View for Ruby on Rails allow remote attackers to access arbitrary files by manipulating file pathnames within applications. This could impact systems processing user-supplied pathnames through the render method, potentially exposing sensitive data. Organizations should take specific steps to address this risk.

Identify applications using affected Ruby on Rails versions.
Restrict file path rendering and limit render method usage.
Update to vendor-provided fixes and monitor for unusual file access.

Frequently asked questions

What is the main function of the Action View component in Ruby on Rails?

The Action View component in Ruby on Rails is responsible for handling the presentation layer of web applications. It allows developers to define how data is displayed to users, often by using templates and views to generate HTML and other output formats. This component is crucial for creating the user interface that users interact with.

What weakness class describes the vulnerability in Ruby on Rails CVE-2016-0752?

The vulnerability CVE-2016-0752 is classified under the weakness class CWE-22, which represents 'Improper Limitation of a Pathname to a Restricted Directory or 'Canonical File' Name'. This means the software does not properly restrict the files that can be accessed via a pathname, allowing attackers to traverse directories and access files outside the intended scope.

How can an attacker exploit the Ruby on Rails directory traversal flaw?

An attacker can exploit this vulnerability by leveraging an application's unrestricted use of the `render` method. By providing a crafted input containing '.. ' (dot dot) in a pathname, an attacker can trick the application into reading arbitrary files from the server's file system, effectively bypassing intended directory restrictions.

How relevant is CVE-2016-0752 to internet-facing applications?

This vulnerability is highly relevant to internet-facing applications built with Ruby on Rails because it affects the Action View component, which is commonly used in web services and APIs. The nature of the vulnerability, allowing remote attackers to read arbitrary files, makes it a significant threat to applications exposed to the internet, especially if the `render` method is used with user-supplied input without proper sanitization.

What practical steps should organizations take to address this Ruby on Rails vulnerability?

Organizations should identify all applications using affected Ruby on Rails versions and immediately update to patched versions provided by the vendor. Additionally, it is crucial to review and restrict the use of the `render` method, particularly when handling user-supplied pathnames, to prevent directory traversal. Monitoring for unusual file access patterns on systems running these applications is also recommended.

References

Written by Nicholas Merritt

External-surface CVE analysis and Halo Surface Signal prioritization for Halo Threat Intelligence.