CVE-2015-7578 in Ruby on Rails
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the rails-html-sanitizer gem before 1.0.3 for Ruby on Rails 4.2.x and 5.x allows remote attackers to inject arbitrary web script or HTML via crafted tag attributes.
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Analysis
by VulDB Data Team • 07/06/2022
The CVE-2015-7578 vulnerability represents a critical cross-site scripting flaw within the rails-html-sanitizer gem, a component widely utilized in ruby on rails applications for sanitizing html content. This vulnerability specifically affects versions prior to 1.0.3 and impacts both ruby on rails 4.2.x and 5.x frameworks, creating a significant security risk for web applications that rely on html sanitization to prevent malicious code injection. The flaw stems from inadequate validation of tag attributes during the sanitization process, allowing attackers to bypass security measures through carefully crafted input.
The technical implementation of this vulnerability exploits the insufficient filtering mechanisms within the html sanitizer, where malicious attributes within html tags are not properly sanitized before being rendered in web browsers. Attackers can inject malicious javascript code or html elements through crafted tag attributes that pass through the flawed sanitization logic, potentially executing arbitrary scripts in the context of the victim's browser session. This type of vulnerability falls under the common weakness enumeration category CWE-79, which specifically addresses cross-site scripting vulnerabilities where untrusted data is improperly sanitized before being rendered in web applications.
The operational impact of CVE-2015-7578 extends beyond simple data theft or defacement, as it enables attackers to perform session hijacking, redirect users to malicious sites, or execute persistent attacks through malicious script injection. The vulnerability is particularly dangerous in web applications that accept user-generated content, as it allows attackers to inject malicious code that persists across multiple user sessions. This creates a persistent threat vector that can compromise user sessions and potentially lead to complete application compromise, especially when combined with other vulnerabilities or attack vectors.
Mitigation strategies for this vulnerability require immediate patching of the rails-html-sanitizer gem to version 1.0.3 or later, which includes proper attribute validation and sanitization routines. Organizations should also implement additional security measures such as content security policies, input validation at multiple layers, and regular security assessments of their ruby on rails applications. The vulnerability demonstrates the importance of proper html sanitization practices and aligns with attack techniques documented in the attack tree framework, where attackers exploit input validation flaws to achieve persistent code execution. Security teams should also consider implementing web application firewalls and monitoring for suspicious attribute patterns that may indicate attempted exploitation of similar vulnerabilities.