HashiCorp Certified: Vault Associate (002) Exam

Vault supports CIDR-bound tokens, which are tokens that can only be used from a specific set of IP addresses or network ranges. This is a way to limit the scope and exposure of a token in case it is compromised or leaked. CIDR-bound tokens can be created by specifying the bound_cidr_list parameter when creating or updating a token role, or by using the -bound-cidr option when creating a token using the vault token create command. CIDR-bound tokens can also be created by some auth methods, such as AWS or Kubernetes, that can automatically bind the tokens to the source IP or network of the client.Reference:Token - Auth Methods | Vault | HashiCorp Developer,vault token create - Command | Vault | HashiCorp Developer

Vault policies are written in HCL or JSON format and are attached to tokens or roles by name. Policies define the permissions and restrictions for accessing and performing operations on certain paths and secrets in Vault.Policies are deny by default, which means that an empty policy grants no permission in the system, and any request that is not explicitly allowed by a policy is implicitly denied1. Some of the features and benefits of Vault policies are:

Policies are path-based, which means that they match the request path to a set of rules that specify the allowed or denied capabilities, such as create, read, update, delete, list, sudo, etc2.

Policies are additive, which means that if a token or a role has multiple policies attached, the effective policy is the union of all the individual policies.The most permissive capability is granted if there is a conflict3.

Policies can use glob patterns, such as * and +, to match multiple paths or segments with a single rule.For example, path ''secret/*'' matches any path starting with secret/, and path ''secret/+/config'' matches any path with two segments after secret/ and ending with config4.

Policies can use templating to interpolate certain values into the rules, such as identity information, time, randomness, etc.For example, path ''secret/{{identity.entity.id}}/*'' matches any path starting with secret/ followed by the entity ID of the requester5.

Policies can be managed by using the vault policy commands or the sys/policy API endpoints.You can write, read, list, and delete policies by using these interfaces6.

The default policy is a built-in policy that is attached to all tokens by default and cannot be deleted. However, the default policy can be modified by using the vault policy write command or the sys/policy API endpoint.The default policy provides common permissions for tokens, such as renewing themselves, looking up their own information, creating and managing response-wrapping tokens, etc7.

You do not have to use YAML to define policies, as Vault supports both HCL and JSON formats.HCL is a human-friendly configuration language that is also JSON compatible, which means that JSON can be used as a valid input for policies as well8.

Vault does not need to be restarted in order for a policy change to take effect, as policies are stored and evaluated in memory. Any change to a policy is immediately reflected in the system, and any token or role that has that policy attached will be affected by the change.

In the HashiCorp Vault UI, secrets are organized in a tree-like structure. To view a secret located at secret/my-secret, you would click on the ''secret/'' folder in the tree, then click on the ''my-secret'' file. In this screenshot, the ''secret/'' folder is located at option C. This folder contains the secrets that are stored in the key/value secrets engine, which is the default secrets engine in Vault. The key/value secrets engine allows you to store arbitrary secrets as key/value pairs. The key is the path of the secret, and the value is the data of the secret. For example, the secret located at secret/my-secret has a key of ''my-secret'' and a value of whatever data you stored there.

[KV - Secrets Engines | Vault | HashiCorp Developer]

A lease ID is a unique identifier that is assigned by Vault to every dynamic secret and service type authentication token. A lease ID contains information such as the secret path, the secret version, the secret type, etc. A lease ID can be used to track and revoke access granted to a job by Vault at completion, as it allows the scheduler to perform the following operations:

Lookup the lease information by using the vault lease lookup command or the sys/leases/lookup API endpoint. This will return the metadata of the lease, such as the expire time, the issue time, the renewable status, and the TTL.

Renew the lease if needed by using the vault lease renew command or the sys/leases/renew API endpoint. This will extend the validity of the secret or the token for a specified increment, or reset the TTL to the original value if no increment is given.

Revoke the lease when the job is completed by using the vault lease revoke command or the sys/leases/revoke API endpoint. This will invalidate the secret or the token immediately and prevent any further renewals. For example, with the AWS secrets engine, the access keys will be deleted from AWS the moment a lease is revoked.

A lease ID is different from a token ID or a token accessor. A token ID is the actual value of the token that is used to authenticate to Vault and perform requests. A token ID should be treated as a secret and protected from unauthorized access. A token accessor is a secondary identifier of the token that is used for token management without revealing the token ID. A token accessor can be used to lookup, renew, or revoke a token, but not to authenticate to Vault or access secrets. A token ID or a token accessor can be used to revoke the token itself, but not the leases associated with the token. To revoke the leases, a lease ID is required.

An authentication method is a way to verify the identity of a user or a machine and issue a token with appropriate policies and metadata. An authentication method is not an object that can be tracked or revoked, but a configuration that can be enabled, disabled, tuned, or customized by using the vault auth commands or the sys/auth API endpoints.

The command vault secrets enable transit enables the transit secrets engine at the transit path. The transit secrets engine is a secrets engine that handles cryptographic functions on data in-transit, such as encryption, decryption, signing, verification, hashing, and random bytes generation. The transit secrets engine does not store the data sent to it, but only performs the requested operations and returns the results. The transit secrets engine can also be viewed as ''cryptography as a service'' or ''encryption as a service''. The command vault secrets enable transit uses the default path of transit for the secrets engine, but this can be changed by using the -path option. For example, vault secrets enable -path=my-transit transit would enable the transit secrets engine at the my-transit path.Reference:Transit - Secrets Engines | Vault | HashiCorp Developer,vault secrets enable - Command | Vault | HashiCorp Developer