Critical Security Flaw in Ruby Package: CGI::Cookie Mismanagement
Summary
ALPINE-CVE-2021-41819: CGI::Cookie.parse in Ruby through 2.6.8 mishandles security prefixes in cookie names. This also affects the CGI gem through 0.3.0 for Ruby. Affects ruby versions < 2.7.5-r0. Fixed in 2.7.5-r0. How to fix ↓
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Background
Ruby is a dynamic, open-source programming language known for its simplicity and productivity. It supports multiple programming paradigms and is widely used for web development, particularly with the Ruby on Rails framework. The CGI module in Ruby handles the Common Gateway Interface, allowing web applications to interact with web servers. However, a vulnerability in the CGI::Cookie component has been identified, which can lead to security issues when handling cookie names.
Vulnerability Detail
The vulnerability, identified as CVE-2021-41819, arises from the CGI::Cookie.parse method in Ruby versions up to 2.6.8. This method mishandles security prefixes in cookie names, potentially allowing attackers to exploit this flaw to manipulate cookie data. The ramifications include unauthorized access to sensitive information, session hijacking, and other security breaches. The vulnerability also affects the CGI gem through version 0.3.0, making it critical for users of these versions to take immediate action.
How To Fix
Minimum fixed version
2.7.5-r0
This is the first release that contains the fix.
sudo apk add --upgrade rubyTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If immediate patching is not feasible, consider implementing input validation on cookie names to filter out potentially harmful prefixes. This can help mitigate the risk until the package is updated.
Conclusion
The vulnerability CVE-2021-41819 poses a significant risk to applications using affected versions of Ruby. It is crucial for developers to update their Ruby packages to the patched versions to safeguard their applications from potential exploits. Utilizing tools like Vulert can help monitor and alert for such vulnerabilities in real-time.
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FAQ
CVE-2021-41819 is a security vulnerability in the Ruby programming language that affects the CGI::Cookie.parse method, leading to potential cookie manipulation.
You can use Vulert, which monitors open-source vulnerabilities in real-time. Simply upload your manifest file like package-lock.json to check for vulnerabilities.
Exploitation of this vulnerability can lead to unauthorized access to sensitive information, session hijacking, and other security breaches.
Yes, patched versions of Ruby are available. Users should update to Ruby 2.7.5-r0 or 3.0.3-r0 depending on their Alpine version.
Implement input validation on cookie names to mitigate risks until you can update to a patched version.
References
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