CVE-2019-5477 : Vulnerability Insights and Analysis

CVE-2019-5477 is a vulnerability related to command injection in Nokogiri v1.10.3 and earlier versions, allowing the execution of commands in a subprocess using the

Kernel.open

method in Ruby.

Understanding CVE-2019-5477

What is CVE-2019-5477?

The vulnerability in CVE-2019-5477 enables the execution of commands in a subprocess through the

Kernel.open

method in Ruby, affecting processes using the undocumented method

Nokogiri::CSS::Tokenizer#load_file

with unsafe user input as the filename.

The Impact of CVE-2019-5477

This vulnerability poses a risk of command injection, potentially leading to unauthorized command execution and system compromise.

Technical Details of CVE-2019-5477

Vulnerability Description

The vulnerability allows for command execution in a subprocess using the

Kernel.open

method in Ruby.

Affected Systems and Versions

Vendor: Nokogiri (ruby gem)
Affected Version: Fixed in v1.10.4

Exploitation Mechanism

The vulnerability arises from the use of the undocumented method

Nokogiri::CSS::Tokenizer#load_file

with unsafe user input as the filename.

Mitigation and Prevention

Immediate Steps to Take

Upgrade Nokogiri to version 1.10.4 or later.
Ensure safe handling of user input to prevent command injection.

Long-Term Security Practices

Regularly update dependencies and libraries to patched versions.
Implement input validation and sanitization to mitigate command injection risks.

Patching and Updates

Upgrade to Nokogiri v1.10.4 or newer versions to address the vulnerability.