Command Injection in Ruby: Examples and Prevention

Websites often face hacking attempts through various methods, with command injection being one of the most dangerous vulnerabilities, allowing attackers to execute arbitrary commands on a host operating system. This post delves into the mechanics of command injection, particularly in Ruby, explaining how it can occur when user inputs are directly passed to system commands, as in the case of creating a directory with user-defined names. Even widely used libraries like ImageMagick and Rake have been susceptible to such vulnerabilities. The article emphasizes avoiding direct execution of system commands in Ruby and suggests preventive measures like sanitizing or parameterizing user inputs, validating inputs, and using Ruby's FileUtils module for file handling. Additionally, the Open3 module is recommended for capturing command output streams securely. Overall, while command injection vulnerabilities offer nearly limitless possibilities for attackers, they can be effectively mitigated by following these best practices.