Two-Factor Authentication @ IfI (2FA)

The main goal of 2-factor authentication (2FA) is to mitigate the impact of successful phishing and malware attacks, whereby attackers might get hold of your if credentials (username + password). Without 2FA, such an attacker could use IfI account credentials to impersonate you, read/delete all your data, etc. With 2FA, there is a second line of defense, namely the 2nd factor which needs to be entered (besides username + password), which is much more difficult to obtain for a remote attacker.

With the above goal in mind, we suggest the following best practices:

• Use a password manager / key chain to store your IfI credentials (username + password) but avoid using the password manager to store the 2nd factor too. Why? Because if an attacker gets hold on your password manager, all is lost.
• Use your mobile phone to provide the second factor (see PUSH and TOTP tokens below).
• To avoid, that your mobile phone becomes a single point of faillure (i.e. no way to login in case the phone is lost or has no power), use a hardware token such as a yubikey. you can easily put it on your (physical) key chain, so you always have it with you. You can use TOTP tokens or passkey with such a yubikey.
• Always protect your 2nd factor:
  • Keep your mobile phone locked, and use a fingerprint or PIN to unlock it (pattern unlock is not of much use, i.e. easily spotted and broken).
  • Keep your hardware token / yubikey in your pocket. If you just keep it plugged to your laptop, anyone can use it who gets hold of your laptop. If you absolutely want to keep the yubikey plugged in, buy a (more expensive) yubikey with fingerprint authentication and/or use PIN protection for the stored passkeys.
  • If you absolutely must store your 2nd factor in your password manager, make sure that you have protected your password manager (auto lock, strong (secret) passphrase to unlock it). And also make sure that your laptop is always locked (screen lock) when you leave it unsupervised (i.e. if you leave the office shortly, etc.). Please note: these two things are absolutely essential anyhow.
  • Enable locking for the authenticator app (PrivacyIDEA / Google / MS authenticator) holding e.g. PUSH and TOTP tokens, such that even if someone gains access to your phone cannot use it without fingerprint or PIN (in addition to locking your mobile phone).

Notes:

• enable locking ⇒ make sure that the authenticator app / password manager is locked (automatically) and needs a fingerprint or a PIN before usage.
• remove Yubikey ⇒ Yubikeys without fingerprint or PIN protection need to be removed from the laptop when not used and stored in a secure location, i.e. together with your other keys in your pocket. Alternatively use Yubikey with fingerprint sensor.

The PrivacyIDEA Authenticator is an app for Android or IOS mobile phones. Besides the standard TOTP (6-digit one-time password) token it also provides the PUSH token, which is a very unobtrusive way to provide the 2nd factor. You only need to confirm the login on your phone and authenticate that with your fiingerprint.

To setup the PUSH token, do the following:

1. Open PrivacyIDEA, click on Enroll Token. The PUSH token should be selected by default.
2. Install the PrivacyIDEA Authenticator on your phone. You can use the QR codes provided to do that.
3. Add a Description (to distinguish your tokens easily) and click Enroll Token.
4. Scan the new QR code with the PrivacyIDEA Authenticator app.

Your PUSH token is now ready to be used.

For all Authenticator apps the procedure is basically the same:

1. Open PrivacyIDEA, click on Enroll Token and choos the TOTP token.
2. If necessary, install the PrivacyIDEA Authenticator on your phone. You can use the QR codes provided to do that.
3. Add a Description (to distinguish your tokens easily) and click Enroll Token.
4. Scan the new QR code with the PrivacyIDEA Authenticator app (or the Authenticator app of your choosing).

Your TOTP token is now ready to be used.

Please check also the official website and setup guide. You can store various kinds of tokens on the Yubikey. We decribe Passkeys and Yubikey OTP tokens here. To work with the yubikey, you will need the Yubico Authenticator, are available at the yubico website.

You can work with passkeys in several ways. One possibility is to store them on the Yubikey, which is much better than to store them in your password manager (or any other software client) on your laptop.

1. Insert the Yubikey, start the YubiKey Authenticator and go to Passkeys. Unlock the passkey store with your PIN, or set a PIN if you have not done that yet.
2. Open PrivacyIDEA, click on Enroll Token and choose the token type Passkey add a Description (to distinguish your tokens easily) and click Enroll Token.
3. Depending on your environment, your password manager might pop-up and ask to store the passkey. Do not store the passkey there, instead close/cancel that dialog. A new dialog box should pop up, asking you for the PIN of your Yubikey passkey store. Enter the pin and follow the instructions, i.e. press the button on the Yubikey.
4. Check the YubiKey Authenticator for the just saved passkey.

Your passkey is now ready to be used a 2nd factor.

You can configure the YubiKey to generate an one-time password (OTP) when simply pressing the button of the yubikey, and you can use this as a 2nd factor.

1. Insert the YubiKey and use to YubiKey Authenticator to setup a Yubico OTP and assign it to the button (short or long touch). Choose Slots ⇒ Short/Long touch ⇒ Yubico OTP.
2. Assign a public ID or simply use the serial (click the diamonds). Generate the Private ID and the Secret key (using the circular arrows).
3. Copy the Secret key and click Save.
4. Open PrivacyIDEA, click on Enroll Token and choose the token type Yubikey AES mode.
5. Paste the Secret key (copied from the YubiKey Authenticator) to the OTP Key field (PrivacyIDEA), add a Description (to distinguish your tokens easily) and click Enroll Token.

Your token is now ready to be used a 2nd factor. When asked for it, place the cursor in the field where you need to enter the 2nd factor and press the button on the YubiKey.

We enforce 2FA also for SSH and sudo. For technical reasons, it is not possible authenticate over keycloak and therefore there is no single sign-on (SSO) for SSH and sudo. This means, that you will have to present your 2nd factor each time you login (SSH) or use sudo. When using SSH and sudo a lot, this can become painful, so there are two mechanisms in place to mitigate this situation a bit:

• if you use key-based authentication with SSH, you will neither need to enter your password, nor a 2nd factor. Check e.g. here on how to setup key-based authentication. Important: check the notes below.
• sudo has a cache time of 2hrs, which means a sudo session will ask for your password and 2nd factor when you use it the first time, but then only again if the session was idle for 2hrs.

To setup key-based authentication and use the ssh-agent, please check the following tutorials (if necessary):

• SSH Essentials: Working with SSH Servers, Clients, and Keys (digital ocean)
• Create SSH Keys with OpenSSH on macOS, Linux, or Windows (digital ocean)

The second tutorial also explains how to use the ssh-agent.