CVE-2011-0446 in Ruby on Rails
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the mail_to helper in Ruby on Rails before 2.3.11, and 3.x before 3.0.4, when javascript encoding is used, allow remote attackers to inject arbitrary web script or HTML via a crafted (1) name or (2) email value.
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Analysis
by VulDB Data Team • 08/03/2024
The vulnerability CVE-2011-0446 represents a critical cross-site scripting flaw in Ruby on Rails web applications that affects versions prior to 2.3.11 and 3.0.4. This issue specifically targets the mail_to helper functionality which is commonly used to generate email links in web applications. The vulnerability arises when the javascript encoding feature is employed in the mail_to helper, creating a pathway for malicious actors to inject arbitrary web scripts or HTML code into the application's output. The flaw manifests through two primary attack vectors involving crafted name or email values that bypass the application's input sanitization mechanisms. This vulnerability falls under CWE-79 which categorizes cross-site scripting attacks as a result of improper input validation and output encoding. The attack surface is particularly concerning as the mail_to helper is a fundamental component in most Ruby on Rails applications, making this vulnerability widespread across the Rails ecosystem.
The technical exploitation of this vulnerability occurs when developers utilize the mail_to helper with javascript encoding enabled, typically through the :encode => :javascript option. When malicious input containing script tags or HTML entities is passed as either the name or email parameter, the helper fails to properly sanitize these inputs before rendering them in the web page. This creates a persistent XSS vector where attackers can execute malicious scripts in the context of other users' browsers. The vulnerability is particularly dangerous because it leverages legitimate application functionality rather than exploiting a separate security flaw, making it harder to detect and prevent. Attackers can craft payloads that, when executed, can steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. The vulnerability operates at the application layer and can be exploited through various attack vectors including web browsers, mobile applications, or any client that renders the affected HTML output.
The operational impact of CVE-2011-0446 extends beyond simple data theft or defacement, as it enables sophisticated attacks that can compromise entire user sessions and potentially escalate to privilege escalation attacks. The vulnerability affects the confidentiality, integrity, and availability of web applications by allowing attackers to inject malicious code that can persist across multiple user sessions. Users who visit pages containing the vulnerable mail_to helper output become potential victims of session hijacking, credential theft, or other malicious activities. The attack can be particularly damaging in applications where users trust the application's content, as the injected scripts appear to originate from legitimate sources. From an attacker's perspective, this vulnerability provides a stealthy method of exploitation since it utilizes standard Rails helper functionality, making it less likely to trigger security monitoring systems that might flag more obvious attack patterns. The vulnerability also impacts the application's security posture by potentially enabling further attacks such as those targeting the application's backend services or other interconnected systems.
Mitigation strategies for CVE-2011-0446 primarily focus on upgrading affected Ruby on Rails versions to the patched releases 2.3.11 and 3.0.4, which contain proper input sanitization and output encoding mechanisms. Organizations should implement comprehensive patch management procedures to ensure all Rails applications are updated promptly. Additionally, developers should avoid using the javascript encoding option in mail_to helpers when possible, or ensure that all inputs are properly sanitized before being passed to the helper. Input validation should be implemented at multiple layers including application-level sanitization and output encoding. Security teams should conduct regular vulnerability assessments and penetration testing to identify potentially vulnerable applications within their infrastructure. The use of web application firewalls and content security policies can provide additional defense-in-depth measures to prevent exploitation of similar vulnerabilities. Organizations should also implement proper security training for developers to understand the risks associated with helper functions and the importance of input validation. This vulnerability aligns with ATT&CK technique T1059.007 which involves the use of scripting languages to execute malicious code, and demonstrates the importance of proper input validation and output encoding as outlined in the OWASP Top Ten security principles.