Two-factor Authorization on Linux server

The article describes the installation under Ubuntu. Used by Google app.

Installing dependencies

You need to install google-authenticator from source, we don’t trust the left PPA? This will require git, build-essential, libpam0g-dev, checkinstall.

git clone https://code.google.com/p/google-authenticator/ cd libpam/ make sudo checkinstall -D sudo dpkg -i libpam_20120827-1_i386.deb 

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Everything, everything is prepared for customization.

Customization

 #  One Time Password     echo "auth required pam_google_authenticator.so" >> /etc/pam.d/common-auth #      SSH. ,   public key    PAM,   OTP   . echo "auth required pam_google_authenticator.so" >> /etc/pam.d/sshd #   ,     .   auth required pam_google_authenticator.so nullok #  OTP        

It is necessary to configure sshd (/ etc / ssh / sshd_config)

 ChallengeResponseAuthentication yes 

Restart sshd (the current session will not be terminated):

 /etc/init.d/ssh restart 

To configure the user, you must run google-authenticator from each user. There will be displayed the secret key for the application , as well as a link to the QR code that can be scanned by the application. The application asks for email - it does not affect the OTP, it is solely for your convenience, you can enter user @ host.