Two step verification for SSH using Google authentication in 3 simple steps

 

 

Google Authenticator (GA)

Google authenticator is a tool which generate 6 digits Time-based One Time Password(TOTP) for authentication which supports authenticator service(GA, Authy, ..).

 

 

Step 1 : Install Google authenticator 

$ sudo apt update

$ sudo apt install libpam-google-authenticator 

 

Step 2 : Configure Google authenticator

$ google-authenticator    

time based authentication - y

 

Scan code using google authenticator ios or android app or type in the secret key

** Copy the emergency scratch codes

• Next type ( y )
  

 

• Type ( y ) to prevent man-in-the-middle attack
  

• Type ( n )
  

• Type ( y ) for rate limiting
  

** If detailed explanation is required please comment. I will make another post with detailed explanation.
 

Step 3 : Configure ssh

$ sudo nano /etc/pam.d/sshd

Add the following line to last line of the file

• auth required pam_google_authenticator.so

 

$ sudo nano /etc/ssh/sshd_config

Find and Replace

• ChallengeResponeAuthentication no

with

• ChallengeResponeAuthentication yes

 

$ sudo systemctl restart sshd 

That it!

Try logging in 

verification code is send to the mobile app