CVE-2021-22881 Scanner

Ruby on Rails, often referred to as Rails, is a server-side web application framework written in Ruby. It is designed to make web application development faster and easier by providing default structures for a database, a web service, and web pages. Rails is used by thousands of developers to build applications such as marketplace sites, content platforms, and social networking sites. The primary users of Rails are developers and companies looking to create scalable, efficient, and modern web applications. Various organizations worldwide utilize Rails for its convention over configuration approach and the ease of adding new features with reusable, modular code. Rails simplifies the task of creating complex applications by offering a streamlined, intuitive code base.

Host Header Injection is a vulnerability where an attacker uses a crafted Host header to manipulate the request's behavior. In Ruby on Rails, this can cause open redirect issues by exploiting allowed host formats in affected versions. This type of vulnerability can redirect users unknowingly to malicious websites. The vulnerability in question is due to the application incorrectly trusting the Host header to determine the proper URL redirection. Exploiting this vulnerability can have significant security implications, such as phishing attacks or malware distribution via malicious redirects. Addressing such vulnerabilities is crucial to maintaining the security integrity of applications built on Ruby on Rails.

The technical aspect of this vulnerability involves the trust put into the Host header by affected Ruby on Rails versions. By crafting a malicious Host header that complies with the allowed formats, attackers can bypass redirection restrictions. The vulnerable endpoint typically checks the Host header value to decide the redirection destination. The parameter that becomes vulnerable is generally the header field 'Host' in incoming HTTP requests. This can lead to scenarios where applications unknowingly aid attackers in redirecting users to harmful sites. Proper fixes have been issued in newer versions to avoid such exploitation.

When exploited, this vulnerability can result in users being redirected to phishing or malware-dropping sites. The implications are severe, with potential financial loss or information theft when users are misled into entering sensitive data on malicious pages. Additionally, it can damage the reputation of the affected application as users lose trust. Redirecting users unauthoritatively also raises legal and compliance issues for the organizations involved. The risks necessitate an urgent update to secure versions to protect users and maintain application integrity. Failure to act could have wide-reaching negative impacts on both the user base and the application service providers.

REFERENCES

• https://hackerone.com/reports/1047447
• https://nvd.nist.gov/vuln/detail/CVE-2021-22881