CVE-2008-5189 in Ruby on Rails
Summary
by MITRE
CRLF injection vulnerability in Ruby on Rails before 2.0.5 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via a crafted URL to the redirect_to function.
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Analysis
by VulDB Data Team • 05/25/2025
The CVE-2008-5189 vulnerability represents a critical CRLF injection flaw in Ruby on Rails frameworks prior to version 2.0.5, exposing applications to sophisticated HTTP response splitting attacks. This vulnerability specifically targets the redirect_to function within the Rails web application framework, which is a fundamental component used for redirecting users between different pages or resources. The flaw stems from inadequate input validation and sanitization of user-supplied data that flows into HTTP header generation processes, creating a pathway for malicious actors to inject arbitrary HTTP headers into server responses. The vulnerability operates at the application layer and can be exploited remotely without requiring authentication or specialized privileges, making it particularly dangerous for web applications that rely on Rails for their core functionality.
The technical mechanism behind this vulnerability involves the manipulation of carriage return line feed sequences within user input that gets processed by the redirect_to function. When Rails processes a URL containing CRLF characters, the framework fails to properly escape or filter these control characters, allowing attackers to inject additional HTTP headers into the response. This injection capability enables attackers to manipulate the HTTP response structure, potentially leading to various malicious outcomes including session hijacking, cross-site scripting attacks, or cache poisoning. The vulnerability is classified under CWE-113 as "Improper Neutralization of CRLF Sequences in HTTP Headers" and aligns with ATT&CK technique T1584.004 for "Compromise of Web Services" and T1584.002 for "Compromise of Web Applications" within the adversary tactics and techniques framework.
The operational impact of this vulnerability extends beyond simple header injection, as it enables attackers to perform HTTP response splitting attacks that can be leveraged for more sophisticated exploitation techniques. When successful, attackers can inject malicious headers that redirect users to phishing sites, inject malicious content into responses, or manipulate browser behavior through header manipulation. The vulnerability affects all Ruby on Rails applications running versions prior to 2.0.5, including those using the framework for web services, content management systems, and e-commerce platforms. The attack vector is particularly concerning because it requires minimal input manipulation and can be executed through simple URL parameter injection, making it accessible to attackers with basic web exploitation knowledge. Organizations relying on vulnerable Rails applications face significant risks including data theft, service disruption, and potential compromise of user sessions.
Mitigation strategies for CVE-2008-5189 primarily focus on immediate version upgrades to Rails 2.0.5 or later, which include proper input validation and sanitization mechanisms for HTTP header generation. Organizations should implement comprehensive input filtering and sanitization procedures that validate and escape all user-supplied data before processing, particularly data that will be used in HTTP header construction. The implementation of Content Security Policy headers and proper HTTP response handling can provide additional layers of protection against header injection attacks. Security teams should conduct thorough vulnerability assessments of all Rails applications to identify and remediate affected versions, while also implementing web application firewalls and intrusion detection systems that can monitor for suspicious header injection patterns. Regular security updates and patch management processes should be established to prevent similar vulnerabilities from emerging in the future, with particular attention to input validation mechanisms across all web application frameworks and components. Organizations should also consider implementing automated security scanning tools that can detect and alert on potential CRLF injection attempts in real-time monitoring environments.