我想在Ubuntu vps服务器上运行wpscan，但遇到ruby错误

首先，我按照以下方法在ubuntu上安装了wpscan

apt-get install git
sudo apt-get install libcurl4-openssl-dev libxml2 libxml2-dev libxslt1-dev ruby-dev build-essential libgmp-dev zlib1g-dev
git clone https://github.com/wpscanteam/wpscan.git

cd wpscan

sudo gem install bundler && bundle install --without test development

然后，当我通过键入ruby wpscan.rb来运行它时 上面说

Could not find ffi-1.9.18 in any of the sources
Run `bundle install` to install missing gems.

当我运行bundle安装时，我得到了输出

extconf failed, exit code 1

Gem files will remain installed in /var/lib/gems/2.4.0/gems/ffi-1.9.18 for
inspection.
Results logged to
/var/lib/gems/2.4.0/extensions/x86_64-linux/2.4.0/ffi-1.9.18/gem_make.out

An error occurred while installing ffi (1.9.18), and Bundler cannot
continue.
Make sure that `gem install ffi -v '1.9.18'` succeeds before bundling.

In Gemfile:
  typhoeus was resolved to 1.3.0, which depends on
    ethon was resolved to 0.10.1, which depends on

谢谢你的帮助