CVE-2019-14809 : Exploit Details and Defense Strategies

In Go versions prior to 1.11.13 and 1.12.x before 1.12.8, a vulnerability exists due to mishandling of incorrectly formed hosts in URLs, potentially leading to an authorization bypass in certain applications.

Understanding CVE-2019-14809

What is CVE-2019-14809?

This CVE involves a vulnerability in the net/url package in Go, where malformed hosts in URLs are not handled correctly, allowing for an authorization bypass in specific scenarios.

The Impact of CVE-2019-14809

The mishandling of malformed hosts in URLs can lead to an authorization bypass in affected applications, enabling attackers to exploit this vulnerability.

Technical Details of CVE-2019-14809

Vulnerability Description

The issue arises when a Host field contains a suffix not present in the Hostname() or Port() functions, involving a non-numeric port number.
Attackers can craft malicious javascript:// URLs with deceptive hostnames.

Affected Systems and Versions

Go versions before 1.11.13 and 1.12.x before 1.12.8 are vulnerable to this issue.

Exploitation Mechanism

Attackers can create URLs with misleading hostnames to potentially bypass authorization mechanisms in affected applications.

Mitigation and Prevention

Immediate Steps to Take

Update Go to versions 1.11.13 or 1.12.8 to mitigate the vulnerability.
Review and sanitize URLs to prevent the inclusion of deceptive hostnames.

Long-Term Security Practices

Regularly monitor for security updates and patches for Go.
Implement input validation to detect and block malicious URLs.

Patching and Updates

Apply the security updates provided by Go to address this vulnerability.