ratonvirus: A Ruby repository from joelind

Rails antivirus made easy. Developed by Mainio Tech.

Ratonvirus allows your Rails application to rat on the viruses that your users try to upload to your site. This works through Rails validators that you can easily attach to your models.

The purpose of Ratonvirus is to act as the glue that binds your Rails application to a virus scanner and file storage engine of your choise.

Setting up scanning for files attached to models:

class Model < ApplicationRecord
  # ...
  validates :file, antivirus: true
  # ...
end

Running manual scans:

puts "File contains a virus" if Ratonvirus.scanner.virus?("/path/to/file.pdf")

Manual scanning works e.g. for file uploads, file object and file paths.

Ratonvirus works with Active Storage out of the box. Support for CarrierWave is also built in, assuming you already have CarrierWave as a dependency.

When to use this?

This gem can be handy if you want to:

Scan files for viruses in Ruby, especially in Rails
Make the scanning logic agnostic of the
- scanner implementation (e.g. ClamAV)
- file storage (e.g. Active Storage, CarrierWave, no storage engine)
Separate testing code for the scanner implementation or the file storage cleanly into its own place.

Prerequisites

There is no fully Ruby-based virus scanner available on the market for a good reason: it is a heavy task. Therefore, this gem may not work as automagically as you are used to with many other gems.

You will need to setup a virus scanner on your machine. If you have done that before, configuration should be rather simple. Instructions are provided for the open source ClamAV scanner in the ratonvirus-clamby documentation.

This gem ships with an example EICAR file scanner to test out the configuration process. This scanner allows you to test the functionality of this gem with no external requirements but it should not be used in production environments.

Installation

Add this line to your application's Gemfile:

gem "ratonvirus"

And then execute:

$ bundle

Add this initializer to your application's config/initializers/ratonvirus.rb:

# config/initializers/ratonvirus.rb
Ratonvirus.configure do |config|
  config.scanner = :eicar
  config.storage = :active_storage
end

After installation, test that the gem is loaded properly in your it is ready to do a sample validation:

$ bundle exec rails ratonvirus:test

This command should show the following message when correctly installed:

Ratonvirus correctly configured.

NOTE:

By default Ratonvirus is set to remove all infected files that it detects after scanning them. If you want to remove this functionality, please refer to the Scanner addons section of the developer documentation.

Usage

Applying the antivirus validator to your models

In order to apply the antivirus validator, you need to have your file uploads handled by a storage backend such as Active Storage. Examples are provided below for the most common options.

Example with Active Storage

Your model should look similar to this:

class YourModel < ApplicationRecord
  has_one_attached :file
  validates :file, antivirus: true # Add this for antivirus validation
end

Example with CarrierWave

Your model should look similar to this:

class YourModel < ApplicationRecord
  mount_uploader :file, YourUploader
  validates :file, antivirus: true # Add this for antivirus validation
end

Please note the extra configuration you need for CarrierWave from the configuration examples.

Manually checking for viruses

For the manual scans to work you need to configure the correct storage backend first that accepts these resources:

# config/initializers/ratonvirus.rb

# When scanning files or file paths only
Ratonvirus.configure do |config|
  config.storage = :filepath
end

# When scanning files, file paths or active storage resources
Ratonvirus.configure do |config|
  config.storage = :multi, {storages: [:filepath, :active_storage]}
end

In case you want to manually scan for viruses, you can use any of the following examples:

# It is a good idea to check first that the scanner is available.
if Ratonvirus.scanner.available?
  # Scanning a file path
  path = "/path/to/file.pdf"
  if Ratonvirus.scanner.virus?(path)
    puts "There is a virus at #{path}"
  end

  # Scanning a File object
  file = File.new(path)
  if Ratonvirus.scanner.virus?(file)
    puts "There is a virus at #{file.path}"
  end
end

Sample configurations

Here are few sample configurations to speed up the configuration process.

Active Storage and ClamAV

Gemfile:

gem "ratonvirus"
gem "ratonvirus-clamby"

Initializer:

# config/initializers/ratonvirus.rb
Ratonvirus.configure do |config|
  config.scanner = :clamby
  config.storage = :active_storage
end

Model:

class YourModel < ApplicationRecord
  has_one_attached :file
  validates :file, antivirus: true
end

For installing ClamAV, refer to ratonvirus-clamby

CarrierWave and ClamAV