Understanding OAuth for ServiceNow integrations with Third-Party Systems

When working on designing and developing an integration between ServiceNow and a third-party system, authentication is one the first things to address. One authentication method that stands out is OAuth.

OAuth, short for “Open Authorization” serves as a method for secure, system-to-system authentication. At its core, OAuth facilitates the authorization of a third-party application (consumer/client) by the resource owner (user) to access their information on another site (resource).

OAuth operates on a set of defined roles and components, each serving a specific purpose in the authentication process:

1. Resource Owner: This is the user who owns the data and has the authority to grant access to it. In the context of ServiceNow, the resource owner is the user whose information is sought by the third-party application.
2. Client/Consumer: The third-party application seeking access to the user’s data is referred to as the client or consumer. This could be any external system or application that needs to integrate with ServiceNow.
3. Authorization Server: ServiceNow acts as the authorization server in the OAuth framework. It validates the identity of the client and issues access tokens upon successful authentication.
4. Resource Server: The resource server is where the user’s data is stored. In the case of ServiceNow, it’s the platform itself. The resource server verifies the access tokens presented by the client to ensure the requested data can be provided.

The OAuth Workflow in ServiceNow Integration works this way:

1. Client Registration: The third-party application registers with ServiceNow, obtaining a client ID and client secret.
2. Authorization Request: The client requests authorization from the resource owner, initiating the authentication process.
3. User Authentication: The resource owner authenticates themselves, granting permission for the third-party application to access their data.
4. Access Token Request: Upon successful authentication, the client requests an access token from the authorization server.
5. Access Token Grant: The authorization server validates the client’s credentials and issues an access token.
6. Accessing Protected Resources: The client presents the access token to the resource server to access the user’s data.

OAuth is a robust and secure authentication protocol. Understanding its components and workflow is crucial for developers working on integrations.