CVE-2012-3465 in Ruby on Rails
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in actionpack/lib/action_view/helpers/sanitize_helper.rb in the strip_tags helper in Ruby on Rails before 3.0.17, 3.1.x before 3.1.8, and 3.2.x before 3.2.8 allows remote attackers to inject arbitrary web script or HTML via malformed HTML markup.
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Analysis
by VulDB Data Team • 03/27/2021
The CVE-2012-3465 vulnerability represents a critical cross-site scripting flaw within the Ruby on Rails web application framework that specifically targets the strip_tags helper functionality. This vulnerability exists in multiple versions of the framework including the 3.0 series before 3.0.17, 3.1 series before 3.1.8, and 3.2 series before 3.2.8, making it a widespread concern for developers and security professionals maintaining Rails-based applications. The flaw is particularly dangerous because it affects the sanitization mechanism that is supposed to protect applications from malicious HTML content, thereby undermining the fundamental security assumptions of web applications built on this framework.
The technical root cause of this vulnerability lies in the improper handling of malformed HTML markup within the strip_tags helper implementation. When developers use this helper to sanitize user input or content before rendering it in web pages, the sanitization process fails to properly parse and neutralize malicious HTML constructs. This occurs because the helper does not adequately validate or process HTML entities and malformed markup patterns that could bypass the intended sanitization filters. Attackers can exploit this by crafting specially formatted HTML content that contains embedded JavaScript code or other malicious scripts, which then execute in the context of other users' browsers when the sanitized content is rendered.
The operational impact of this vulnerability is severe and far-reaching for any Ruby on Rails application that relies on the strip_tags helper for content sanitization. Remote attackers can inject arbitrary web scripts or HTML code into web pages, potentially leading to session hijacking, credential theft, data exfiltration, or the execution of malicious commands on victim machines. The vulnerability creates a persistent threat vector where attackers can maintain access to affected systems through persistent XSS payloads, making it particularly dangerous for applications that store user-generated content or allow rich text editing. This type of attack can compromise the integrity and confidentiality of user data, potentially affecting thousands of users depending on the scale of the affected application.
Security professionals should immediately implement mitigation strategies including upgrading to patched versions of Ruby on Rails, specifically versions 3.0.17, 3.1.8, and 3.2.8, which contain the necessary fixes for this vulnerability. Additionally, organizations should conduct comprehensive security audits of their Rails applications to identify all potential uses of the strip_tags helper and implement additional input validation measures. The vulnerability aligns with CWE-79 which classifies cross-site scripting as a critical weakness in web applications, and it maps to ATT&CK technique T1566 which covers social engineering through malicious content injection. Organizations should also consider implementing Content Security Policy headers as an additional defense-in-depth measure, though this cannot fully compensate for the underlying vulnerability in the sanitization library itself.