ntlm-sso

https://github.com/rekado/ntlm-sso

A Rack middleware interface to automatically authenticate users via NTLM. This module stores the user name in the environment variable REMOTE_USER upon success. Upon failure the REMOTE_USER variable is either left empty or filled with a default value, dependent on configuration. Failure to authenticate does not result in an error as authorisation is to be handled by your application based on the value in REMOTE_USER.