» TOTP MFA

This page demonstrates the TOTP MFA on ACL'd paths of Vault.

» Configuration

  1. Enable the appropriate auth method:

    $ vault auth enable userpass
    
  2. Fetch the mount accessor for the enabled auth method:

    $ vault auth list -detailed
    

    The response will look like:

    Path         Type        Accessor                  Plugin    Default TTL    Max TTL    Replication    Description
    ----         ----        --------                  ------    -----------    -------    -----------    -----------
    token/       token       auth_token_289703e9       n/a       system         system     replicated     token based credentials
    userpass/    userpass    auth_userpass_54b8e339    n/a       system         system     replicated     n/a
    
  3. Configure TOTP MFA:

    $ vault write sys/mfa/method/totp/my_totp \
        issuer=Vault \
        period=30 \
        key_size=30 \
        algorithm=SHA256 \
        digits=6
    
  4. Create a policy that gives access to secret through the MFA method created above:

    $ vault policy write totp-policy -<<EOF
    path "secret/foo" {
      capabilities = ["read"]
      mfa_methods  = ["my_totp"]
    }
    EOF
    
  5. Create a user. MFA works only for tokens that have identity information on them. Tokens created by logging in using auth methods will have the associated identity information. Create a user in the userpass auth method and authenticate against it:

    $ vault write auth/userpass/users/testuser \
        password=testpassword \
        policies=totp-policy
    
  6. Create a login token:

    $ vault write auth/userpass/login/testuser \
        password=testpassword
    
    Key                    Value
    ---                    -----
    token                  70f97438-e174-c03c-40fe-6bcdc1028d6c
    token_accessor         a91d97f4-1c7d-6af3-e4bf-971f74f9fab9
    token_duration         768h
    token_renewable        true
    token_policies         [default totp-policy]
    token_meta_username    "testuser"
    

    Note that the CLI is not authenticated with the newly created token yet, we did not call vault login, instead we used the login API to simply return a token.

  7. Fetch the entity ID from the token. The caller identity is represented by the entity_id property of the token:

    $ vault token lookup 70f97438-e174-c03c-40fe-6bcdc1028d6c
    
    Key                 Value
    ---                 -----
    accessor            a91d97f4-1c7d-6af3-e4bf-971f74f9fab9
    creation_time       1502245243
    creation_ttl        2764800
    display_name        userpass-testuser
    entity_id           307d6c16-6f5c-4ae7-46a9-2d153ffcbc63
    expire_time         2017-09-09T22:20:43.448543132-04:00
    explicit_max_ttl    0
    id                  70f97438-e174-c03c-40fe-6bcdc1028d6c
    issue_time          2017-08-08T22:20:43.448543003-04:00
    meta                map[username:testuser]
    num_uses            0
    orphan              true
    path                auth/userpass/login/testuser
    policies            [default totp-policy]
    renewable           true
    ttl                 2764623
    
  8. Generate TOTP method attached to the entity. This should be distributed to the intended user to be able to generate TOTP passcode:

    $ vault write sys/mfa/method/totp/my_totp/admin-generate \
        entity_id=307d6c16-6f5c-4ae7-46a9-2d153ffcbc63
    
    Key        Value
    ---        -----
    barcode    iVBORw0KGgoAAAANSUhEUgAAAM...
    url        otpauth://totp/Vault:307d6c16-6f5c-4ae7-46a9-2d153ffcbc63?algo...
    

    Either the base64 encoded png barcode or the url should be given to the end user. This barcode/url can be loaded into Google Authenticator or a similar TOTP tool to generate codes.

  9. Login as the user:

    $ vault login 70f97438-e174-c03c-40fe-6bcdc1028d6c
    
  10. Read the secret, specifying the mfa flag:

    $ vault read -mfa my_totp:146378 secret/foo
    
    Key                 Value
    ---                 -----
    refresh_interval    768h
    data                which can only be read after MFA validation