Secrets Management: Features and Functions (updated)
In this section we will discuss the core features of a secrets management platform. There are basic functions every secrets management platform needs to address the basic use cases. These include secure storage and disbursement of secrets, identity management, and API access, for starters. There are plenty of tools out there, many open source, and several bundled into other platforms. But when considering what you need from one of these platforms, the key thing to keep in mind is that most of them were originally developed to perform a single very specific task – such as injecting secrets into containers at runtime, or integrating tightly with a Jenkins build server, or supplementing a cloud identity service. Those do one thing well, but typically do not address multiple use cases. Now let’s take a closer look at the key features. Core Features Storing Secrets Secrets management platforms are software applications designed to support other applications in a very important task: securely storing and passing secrets to the correct parties. The most important characteristic of a secrets management platform is that it must never leave secret information sitting around in clear text. Secure storage is job #1. Almost every tool we reviewed provides one or more encrypted repositories – which several products call a ‘vault’ – to store secret information in. As you insert or update secrets in the repository, they are automatically encrypted prior to being written to storage. Shocking though it may be, at least one product you may come across does not actually encrypt secrets – instead storing them in locations its developers consider difficult to access. The good news is that most vaults use vetted implementations of well-known encryption algorithms to encrypt secrets. But it is worth vetting any implementation, with your regulatory and contractual requirements in mind, prior to selecting one for production use. With the exception of select platforms which provide ‘ephemeral secrets’ (more on these later), all secret data is stored within these repositores for future use. Nothing is stored in clear text. How each platform associates secrets with a given user identifier, credential, or role varies widely. Each platform has its own way of managing secrets internally, but mostly they use a unique identifier or key-value pair to identify each secret. Some store multiple versions of a secret so changes over time can be recalled if necessary for recovery or auditing, but the details are part of their secret sauce. The repository structure varies widely between offerings. Some store data in simple text or JSON files. Some use key-value pairs in a NoSQL style database. Others use a relational or Big Data database of your choice. A couple employ multiple repository types to increase isolation between secrets and/or use cases. Their repository architecture is seldom determined by strong security; more common drivers are low cost and ease of use for the product developers. And while a repository of any type can be secured, the choice of repository impact scalability, how replication is performed, and how quickly you can find and provision secrets. Another consideration is which data types a repository can handle. Most platforms we reviewed can handle any type of data you want to store: string values, text fields, N-tuple pairings, and binary data. Indexing is often performed automatically as you insert items, to speed lookup and retrieval later. Some of these platforms really only handle string, which simplifies programmatic API but limits their usability. Again, products tailored to a particular use case may be unsuitable for other uses or across teams. Identity and Access Management Most secrets management platforms concede IAM to external Active Directory or LDAP services, which makes sense because most firms already have IAM infrastructure in place. Users authenticate to the directory store to gain access, and the server leverages existing roles to determine which functions and secrets the user is authorized to access. Most platforms are also able to use a third-party Cloud Identity Service or Privileged Access Management service, or to directly integrate with cloud-native directory services. Note that a couple of the platforms we reviewed manage identity and secrets internally, rather than using an external identity store. This is not a bad thing because they then tend to include secrets management to supplement password or key management, and internally management of identity is part of their security architecture. Access and Usage Most platforms provide one or more programming interfaces. The most common, to serve secrets in automated environments, is an access API. A small and simple set of API calls are provided to authenticate a session, insert a record, locate a secret, and share a secret to a specific user or service. More advanced solutions also offer API access to advanced or administrative functions. Command-line access is also common, leveraging the same basic functions in a command-driven UNIX/Linux environment. A handful of others also offer a graphical user interface, either directly or indirectly, sometimes through another open source project. Sharing Secrets The most interesting aspect of a secrets management system is how it shares secrets with users, services, or applications. How do you securely provide a secret to its intended recipient? As in the repository, as discussed above, secrets in transit must be protected, which usually means encryption. And there are many different ways to pass secrets around. Let’s take a look at the common methods of secret passing. Encrypted Network Communications: Authenticated service or users are passed secrets, often in clear text, within an encrypted session. Some use Secure Sockets Layer (SSL), which is not ideal, for encrypted transport, but thankfully most use current versions of Transport Layer Encryption, which als authenticates the recipient to the secrets management server. PKI: Several secrets management platforms combine external identity management with a Public Key Infrastructure to validate recipients of secrets and transmit PKI encrypted payloads. The platform determines who will receive a secret, and encrypts the content with the recipient’s public key. This ensures that only the intended recipient can decrypt the secret, using their private key.
