CVE-2011-1497 in Ruby on Rails
Summary
by MITRE • 10/19/2021
A cross-site scripting vulnerability flaw was found in the auto_link function in Rails before version 3.0.6.
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Analysis
by VulDB Data Team • 10/23/2021
The vulnerability identified as CVE-2011-1497 represents a critical cross-site scripting flaw within the Ruby on Rails web application framework that affected versions prior to 3.0.6. This security issue resides in the auto_link function, which is commonly used to automatically convert URLs and email addresses into clickable hyperlinks within web applications. The flaw arises from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-provided data before rendering it in web pages. Attackers can exploit this vulnerability by crafting malicious input that contains script tags or other malicious code within URL parameters or email addresses that get processed by the auto_link function. The vulnerability directly maps to CWE-79, which describes Cross-Site Scripting flaws where untrusted data is incorporated into web pages without proper validation or encoding, making it a prime target for malicious actors seeking to execute arbitrary scripts in users' browsers.
The technical exploitation of this vulnerability occurs when user-supplied data containing malicious script code is passed through the auto_link function in Rails applications. The function fails to adequately escape or sanitize special characters such as angle brackets, quotes, and other HTML metacharacters that could be interpreted by browsers as executable code. When this malformed data is rendered in web pages, browsers execute the embedded scripts, potentially allowing attackers to steal session cookies, redirect users to malicious sites, or perform other harmful actions. The impact is particularly severe because the auto_link function is widely used across Rails applications for processing user input, making this vulnerability pervasive throughout the Rails ecosystem. This flaw demonstrates a classic failure in the principle of least privilege and proper data sanitization, where the framework itself becomes a vector for malicious code execution rather than a protective barrier.
The operational impact of CVE-2011-1497 extends beyond simple script execution, as it fundamentally compromises the security model of affected Rails applications. Attackers can leverage this vulnerability to establish persistent access to user sessions, enabling them to impersonate legitimate users and gain unauthorized access to sensitive data or application functionality. The vulnerability also affects the integrity of web applications by allowing attackers to inject malicious content that can be cached or stored in application databases, potentially affecting multiple users over time. Organizations running vulnerable Rails applications face significant risks including data breaches, regulatory compliance violations, and reputational damage. The widespread adoption of Rails means that numerous high-profile applications were potentially exposed to this vulnerability, making it a critical concern for security teams across various industries including finance, healthcare, and government sectors where web application security is paramount.
Mitigation strategies for CVE-2011-1497 primarily focus on immediate application updates and defensive coding practices. The most effective solution involves upgrading to Rails version 3.0.6 or later, where the auto_link function has been patched to properly sanitize input data and prevent script injection. Organizations should also implement comprehensive input validation at multiple layers of their applications, including client-side and server-side validation to reduce the attack surface. Security teams should conduct thorough code reviews to identify any custom implementations of similar functionality that might be vulnerable to the same class of attacks. Additional defensive measures include implementing content security policies, using proper output encoding techniques, and establishing robust application monitoring to detect suspicious activities. The vulnerability highlights the importance of adhering to the principle of defense in depth and following security best practices such as those outlined in the OWASP Top Ten and NIST cybersecurity frameworks to prevent similar issues in future application development cycles.