Duo MFA

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

Configuration

1. Enable the appropriate auth method:

   $ vault auth enable userpass
   

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2. Fetch the mount accessor for the enabled auth method:

   $ vault auth list -detailed
   

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   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
   

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3. Configure Duo MFA:

   $ vault write sys/mfa/method/duo/my_duo \
       mount_accessor=auth_userpass_54b8e339 \
       integration_key=BIACEUEAXI20BNWTEYXT \
       secret_key=HIGTHtrIigh2rPZQMbguugt8IUftWhMRCOBzbuyz \
       api_hostname=api-2b5c39f5.duosecurity.com
   

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4. Create a policy that gives access to secret through the MFA method created above:

   $ vault policy write duo-policy -<<EOF
   path "secret/foo" {
     capabilities = ["read"]
     mfa_methods  = ["my_duo"]
   }
   EOF
   

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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=duo-policy
   

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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 duo-policy]
   token_meta_username    "testuser"
   

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   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 duo-policy]
   renewable           true
   ttl                 2764623
   

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8. Login as the user:

   $ vault login 70f97438-e174-c03c-40fe-6bcdc1028d6c
   

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9. Read a secret to trigger a Duo push. This will be a blocking call until the push notification is either approved or declined:

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

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