Rails provides several tools to protect against common issues such as mass assignment, N+1 queries, and credential protection. Mass assignment protection is achieved through strong parameters, which allow developers to specify which attributes are allowed to be passed to the controller. Strong parameters can be defined at both the model and controller levels, providing flexibility in how they are used. Rails also provides a mechanism for detecting down N+1s through strict loading, which raises an error if the association is lazily loaded. This helps prevent performance issues with large datasets. Credential protection is achieved through the use of encrypted YAML files stored in the application's configuration directory. These files can be accessed using the `credentials` method on Rails applications. Additionally, Rails provides several mechanisms for preventing unwanted emails from being sent during development, including turning off email delivery, changing the delivery method, and intercepting all emails sent in development.