CVE-2020-11076 Explained : Impact and Mitigation

In Puma (RubyGem) before 4.3.4 and 3.12.5, an attacker could smuggle an HTTP response by using an invalid transfer-encoding header. The vulnerability has been assigned CVE-2020-11076.

Understanding CVE-2020-11076

This CVE pertains to a vulnerability in the Puma RubyGem that could allow an attacker to manipulate HTTP responses.

What is CVE-2020-11076?

CVE-2020-11076 is a security vulnerability in Puma (RubyGem) versions prior to 4.3.4 and 3.12.5, enabling attackers to smuggle HTTP responses through a specific header.

The Impact of CVE-2020-11076

The vulnerability poses a high severity risk with a CVSS base score of 7.5. It could lead to integrity impact, allowing attackers to manipulate HTTP responses.

Technical Details of CVE-2020-11076

Vulnerability Description

The issue arises from an inconsistency in interpreting HTTP requests, known as 'HTTP Request Smuggling' (CWE-444), allowing attackers to manipulate responses.

Affected Systems and Versions

Affected versions include Puma < 3.12.5 and >= 4.0.0, < 4.3.4

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Network
Integrity Impact: High
Privileges Required: None

Mitigation and Prevention

Immediate Steps to Take

Update Puma to version 3.12.5 or 4.3.4 to mitigate the vulnerability.
Monitor for any suspicious HTTP responses that could indicate exploitation.

Long-Term Security Practices

Regularly update software components to patch known vulnerabilities.
Implement secure coding practices to prevent similar HTTP smuggling attacks.

Patching and Updates

Apply security patches provided by Puma promptly to address the vulnerability.