Configuring and using certificates to access ITS servers

Owned by Tony Lam
Last updated: Jul 26, 2023 by Tony Lam
3 min read

This document is in progress!

Summary

Passwords alone are no longer sufficient. To address this RIT has moved to Duo's MFA service for the majority of services. Admins and developers, however, have access to large amounts of information and have privileges on servers that can cause significant damage if their credentials are compromised. Because of those risks, stronger and more efficient MFA is required for certain accounts. To achieve this, ITS has historically used OATH (One Time Passwords) for SSH and sudo access on Linux servers and recently started requiring either certificates + PIN or Duo for Windows logons.

OATH is deprecated and all OATH users are being moved to certificate-based authentication. ITS is issuing YubiKeys that will be used to securely generate and store these certificates.

Requirements

Requesting a YubiKey

Considerations

  • These docs are not the only way to accomplish the goal nor are YubiKeys the only way to accomplish password-less authentication however the further you deviate from these docs the less knowledge ITS has to assist you.
  • The OS requires a lock on the YubiKey. If using multiple computers, even if a computer is virtual, multiple devices will be needed – one device per instance of the OS.
    • A YubiKey can be passed through RDP session(s) (Windows only)
  • Each device will have a different certificate. A certificate can, however, be used for access to both Linux and Windows servers.
  • Expert mode: While a YubiKey (i.e. a Yubico device) is not required, the docs and process are assuming a YubiKey is being used. Any device that can securely generate and store keys in a way that can be cryptographically verified will work.


Process Overview

I. Certificate Enrollment
II. Submit certificate for verification
III. Configure clients to use certificates
IV. Next steps

I. Certificate Enrollment


 Certificate Enrollment

Enrollment

  1. Ensure YubiKey is plugged in.

    1. Ensure Yubikey has default MGMT pin, if not run the following command:
      ykman piv access change-management-key -m <MGMKEY> -n 01020304050607080102030405060708010203040506070

  2. Remote desktop to enroll01.ad.rit.edu
    1. Enter enroll01.ad.rit.edu into the Computer: 
    2. Select Show Options dropdown in the bottom left.
    3. Select the Advanced tab.
    4. Select Settings... from the Connect from anywhere.
    5. Select Use these RD Gateway server settings: and enter "rdgateway.rit.edu" as the Server name. 
    6. Select OK.
    7. Select Connect.
    8. Enter RIT credentials with username MAIN\xxxxxx where "xxxxxx" is your username.
    9. Enter credentials again.
       

  1. Multi-factor with DUO (will do so automatically)


  2. Double-click on the Autoenroll.bat


  3. Enter PIN 123456 when prompted. When complete, the command prompt window will go away.
    1. Note: 123456 is the default Yubikey PIN.

      Change PIN (if default)

  4. Send Ctrl-Alt-Del through RDP (Ctrl-Alt-End) and click on Change a password


  5. Click on Sign-in options and then Smart card


  6. Enter the default PIN and your new PIN

II. Submit certificate for verification


 YubiKey Attestation and Submission

Attestation

  1. Insert YubiKey

  2. Open a local Terminal (Linux/Mac) or PowerShell (Windows).

     Windows

    Windows: Run the following to adding the Yubikey Manager cli tools to environment PATH

    #User Level
$newPath = "$env:ProgramFiles\Yubico\Yubikey Manager;" + [Environment]::GetEnvironmentVariable("PATH", [EnvironmentVariableTarget]::User)
[Environment]::SetEnvironmentVariable("PATH", $newPath, [EnvironmentVariableTarget]::User)

    Note: you must close and re-open your PowerShell for these to be picked up

  3. Run the following command to attest the certificate in slot 9a (You will need to rerun for other slots, like 9d)

    Linux users will need to locate the AppImage and execute ykman command as argument

    ykman piv keys attest 9a <path to save attested certificate>
---
Example:
(Windows) ykman piv keys attest 9a $env:HOMEPATH\$env:USERNAME-attest.pem
(Linux) yubikey-manager-qt-***-linux.AppImage ykman piv keys attest 9a $HOME/$USER-attest.pem
(Mac) /Applications/YubiKey\ Manager.app/Contents/MacOS/ykman piv keys attest 9a $HOME/$USER-attest.pem
    1.  This step only needed if requested from cpu.rit.edu

      Run the following to pull the intermediate certificate from slot f9

      Linux users will need to locate the AppImage and execute ykman command as argument

      ykman piv certificates export f9 <path to save attested certificate>
---
Example:
(Windows) ykman piv certificates export f9 %USERPROFILE%\yubico-intermediate-ca.pem
(Linux) yubikey-manager-qt-***-linux.AppImage ykman piv certificates export f9 $HOME/yubico-intermediate-ca.pem
(Mac) /Applications/YubiKey\ Manager.app/Contents/MacOS/ykman piv certificates export f9 $HOME/yubico-intermediate-ca.pem

  4. Print the contents of the ($username-attest.pem).

    (Windows) Get-Content $env:HOMEPATH\$env:USERNAME-attest.pem
(Linux/Mac) cat $HOME/$USER-attest.pem

  5. This step is mainly required for access to Linux servers.
    Paste all the contents of the file ($username-attest.pem), including the "BEGIN/END" statements, into the website below.

    Students: Please log in with your student employee account.

    This is still being tested, but we are using this for now.

    Open in New Tab/Window: https://cpu.rit.edu/yubikey 

     Click here to expand...

    3/18/2022 - (Used for testing only):  Open in New Tab/Window: https://cpu.rit.edu/yubikey 

    Paste all the contents of the file, including the "BEGIN/END" statements

    If submitting multiple certs, each certificate must be merged before new can be added (I believe this is true, needs verification)

    Please inform someone from Operations (Infrastructure Apps/Networks/Systems) that you've uploaded a certificate.
    This step may require a face-to-face meeting or camera-enabled Zoom meeting.

III. Configure clients to use certificates

Windows: III. YubiKey Windows SSH Client Configuration


Mac: III. YubiKey Mac SSH Client Configuration


Linux: III. YubiKey Linux SSH Client Configuration


IV. Next steps

YubiKey Duo Setup - start.rit.edu/Duo

Other uses for certificates

Other uses of YubiKeys

Troubleshooting