CVE-2019-20444 : Exploit Details and Defense Strategies

Netty before 4.1.44 allows an HTTP header without a colon, leading to misinterpretation as a separate header or an invalid fold.

Understanding CVE-2019-20444

In versions of Netty prior to 4.1.44, a vulnerability in the HttpObjectDecoder.java file allows the inclusion of an HTTP header without a colon, potentially causing misinterpretation.

What is CVE-2019-20444?

This CVE refers to a vulnerability in Netty that permits the inclusion of an HTTP header lacking a colon, which may lead to misinterpretation as a separate header with incorrect syntax or as an "invalid fold."

The Impact of CVE-2019-20444

The vulnerability can result in the misinterpretation of an HTTP header, potentially causing errors in header processing and leading to security risks.

Technical Details of CVE-2019-20444

Netty before version 4.1.44 is affected by this vulnerability.

Vulnerability Description

The HttpObjectDecoder.java file in Netty allows the inclusion of an HTTP header without a colon, leading to potential misinterpretation during header processing.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: All versions prior to 4.1.44

Exploitation Mechanism

The vulnerability arises from the improper handling of HTTP headers lacking a colon, which can be mistakenly processed as separate headers or invalid folds.

Mitigation and Prevention

To address CVE-2019-20444, follow these steps:

Immediate Steps to Take

Update Netty to version 4.1.44 or newer to mitigate the vulnerability.
Monitor vendor advisories and security mailing lists for patches and updates.

Long-Term Security Practices

Regularly update software components to the latest versions to address known vulnerabilities.
Implement secure coding practices to prevent similar issues in the future.

Patching and Updates

Apply patches provided by Netty promptly to ensure the security of the system.