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The evolution of digital authentication from simple, unencrypted credentials to today’s advanced methods underscores the importance of data security. As organizations adapt to hybrid deployments and integral application access is no longer within the perimeter of a network, inherited authentication complexity and risk ensue. The adoption of standard authentication protocols and advanced workflows is mandatory to not only reduce risk but also maintain operational stability amongst users who require access to various applications. Okta provides solutions to these inherent industry problems with its comprehensive SaaS platform for Identity and Access Management (IAM) services.

We will examine Okta's services and solutions in the context of Software-as-a-Service (SaaS) platforms and against the backdrop of the broader threat landscape. We'll explore historical and potential vulnerabilities to understand their origins and impacts. This article will provide insights into:

• Universal Directory (UD)
• Data Model
• API Access Management
• Access Policies
• Session Management
• Tenants
• Authorization Workflows
• Authentication Workflows.

With a deeper understanding of Okta, security practitioners may leverage this knowledge to accurately assess attack surfaces where Okta is deployed.

Okta's offerings

Overview of core services

In this introduction, we delve into the core services provided by Okta. Primarily, Okta is a SaaS platform, specializing in scalable Identity and Access Management (IAM) solutions. Central to its offerings are technologies such as Single Sign-On (SSO), Multi-Factor Authentication (MFA), and support for complex multi-tenant architectures. Okta also boasts a robust suite of RESTful APIs, facilitating seamless Create, Read, Update, and Delete (CRUD) operations.

At the heart of Okta’s IAM solutions lie users, groups, and policies. The platform provides comprehensive lifecycle management and a UD, allowing seamless IAM across hybrid environments encompassing applications, devices, and more. This includes synchronization capabilities with external directories like LDAP or Active Directory (AD), ensuring a unified identity management system.

A key aspect of Okta's service is its dual role as both a Service Provider (SP) and an Identity Provider (IdP). This dual functionality enables Okta to facilitate secure and seamless authentication via its Identity Engine, and robust authorization using standard protocols such as OAuth, while also supporting authentication protocols such as Security Assertion Markup Language (SAML) and OpenID Connect (OIDC).

For customers, Okta offers valuable tools for security and compliance. System logs, environment-based events that are stored and retrievable via API, provide insights into user activities and organizational events. These logs are crucial for Security Information and Event Management (SIEM) systems, aiding in the detection of anomalies and potential threats.

Additionally, Okta's ThreatInsight feature stands out as a proactive security measure. It aggregates and analyzes system logs, dynamically identifying and responding to potential threats. This includes recognizing patterns indicative of malicious activities such as password spraying, credential stuffing, and detecting suspicious IP addresses. These features collectively enhance the security posture of organizations, fortifying them against a wide array of cyber threats.

Integration capabilities

Aside from some of the many offerings, Okta is very developer-friendly with various other SaaS solutions and applications. Out of the box, Okta contains an integration network that allows seamless integration with other applications such as Slack, Google Workspace, Office 365, GitHub, and many more.

Okta’s RESTful APIs follow the System for Cross-domain Identity Management (SCIM) protocol. This allows for straightforward Create, Read, Update, and Delete (CRUD) operations on users and groups by applications or developers, but also enables standardization within the SaaS ecosystem. SCIM is a pivotal component of Okta's scalability. As businesses expand, the need to integrate an increasing number of users, groups, and access controls across various SaaS platforms grows. SCIM addresses this challenge by standardizing how user identity data is communicated between these platforms. This standardization facilitates the process of user management, especially in synchronizing user information across different systems.

Okta’s object management regarding APIs is focused on several domains listed below:

• Apps API - Manage applications and their association with users and groups.
• Users API - CRUD operations on users.
• Sessions API - Creates and manages user’s authentication sessions.
• Policy API - Creates and manages settings such as a user’s session lifetime.
• Factors API - Enroll, manage, and verify factors for MFA.
• Devices API - Manage device identity and lifecycles.

When integrations are added to an Okta organization, authentication policies, both fine-grained and global, can be set up for access control based on end-user attributes stored within the user’s Okta profile.

Universal directory

At the core of Okta’s user, group, policy, and device management is the UD. This is a single pane view of all assets, whether sourced from Okta, an integration, or a secondary directory service such as AD.

The UD is technically an Okta-managed, centralized, and cloud-based repository for all user, group, device, and policy profiles. Okta is either the source of truth regarding IAM or synchronizes with other federation services and identity providers such as AD or Google Workspace. The UD is accessible behind Okta’s core APIs for CRUD operations and used in conjunction with their single sign-on (SSO) platform, thus providing authentication and authorization to linked integrations or the admin console itself. Everything from user management to streamlined password management is enabled by the UD.

In conclusion, the UD classifies as a directory-as-a-service (DaaS), similar to AWS directory service, Microsoft’s Entra ID and many more.

Customization and management

Adding a bit more depth to the UD, profile customization is accessible. This enables an organization to store a record of information regarding users and groups that contain specific attributes. Base attributes are assigned by Okta, but custom attributes can be added as well between user, group, and app user profiles. Attribute mappings are important for synchronization and data exchanges between integrations and other directory services. For example, the AD attribute givenName can be mapped specifically to FirstName and LastName in Okta. Aside from synchronization, this is important for other Okta-related features such as inline hooks, directory rules and actions, and more.

Additionally, this enables rich SAML assertions and WS-Federation claims where applications can utilize this information to create rich user accounts, update accounts, or create complex authorization and authentication decisions.

There are additional autonomous provisioning and deprovisioning options available as well with the UD and internal profiles, important for scalability and administrative tasks such as controlling which user types can access which applications, thus enabling more traditional role-based access control (RBAC) policies.

Integration with external directories

As mentioned previously, the Okta Directory Integration can synchronize with external directories such as LDAP, AD, Google Workspace and others. For cloud-based DaaS platforms, Okta leverages RESTful APIs and the SCIM protocol to perform data exchanges and more. For on-premise environments, Okta has an AD endpoint agent that can be deployed and thus pulls information from directory services and ships it back to the UD.

Alternatively, Desktop SSO (DSSO) provides an agentless option as well. This supplies flexibility to cloud, on-premise or hybrid based environments all while continuing scalability and direct integration with 3rd-party applications. Architecturally, this solves the many pitfalls of LAN-based environments, where applications are served to domain users behind a firewall. From a security perspective, credentials and profiles are then synchronized from all application directories into a single “source-of-truth”: Okta. It is much more approachable to audit a single directory as well in an instance where, for example, a disgruntled employee is no longer employed, and thus access across various applications must be deactivated. Single Log-Off (SLO) is thus available for such situations thanks to these external directory integration capabilities.

Finally, we must not overlook the amount of maintenance this potentially reduces for organizations who may not have the resources to manage SAML, OAuth, and SCIM communications between RESTful APIs or compatibility issues between integrations as Okta manages this for them.

Additional solutions and examples of Okta providers with external directory support for AD can be found here.

Data model

As we traverse through the Okta landscape, understanding Okta’s data models is important to security practitioners who may be tasked with threat hunting, detection logic, and more.

Structure and design

When Okta is first established for an organization, it inherits its own “space” where applications, directories, user profiles, authentication policies, and more are housed. A top-level directory resource is given as a “base” for your organization where entities can be sourced from Okta or externally (LDAP, AAD, Google Workspace, etc.).

Okta users are higher-privileged users who typically leverage the Okta admin console and perform administrative tasks, while end users are those who may rely on Okta for SSO, access to applications and more.

By default, entities in Okta are referred to as resources. Each resource has a combined set of default and custom attributes as discussed before. Links then describe relationships or actions that are acceptable for a resource, such as a deactivation link. This information is then aggregated into a profile which is then accessible from within the UD. Groups are made up of users more as a label to a specific set of users.

Applications hold information about policies for access related to users and groups, as well as how to communicate with each integrated application. Together, the data stored about application access and related users is stored as an AppUser and if mapping is done correctly between directories, enables access for end users.

A policy contains a set of conditions and rules that affect how an organization behaves with applications and users. Policies are all-encompassing in Okta, meaning they are used for making decisions and completing actions such as - what is required for a password reset or how to enroll in MFA. These rules can be expressed using the Okta Expression Language (OEL).

Dedicated authorization servers are used per organization to provide authorization codes and tokens for access to applications by API or resources. Here, authorization and authentication protocols such as OAuth, OIDC, and SAML are vital for workflows. These authorization servers are also responsible for communication with third-party IdPs such as Google Workspace. End users who may seek access to applications are entangled in communication between authorization servers and SPs as codes and tokens are exchanged rapidly to confirm authorization and authentication.

Altogether, this structure and design support scalability, customization, and seamless integration.

API access management

API access management is not only important for end users, administrators, and developers but also for integration-to-integration communication. Remember that at the forefront of Okta are its various RESTful API endpoints.

While we won’t dive deep into the design principles and object management of Okta’s APIs, we will attempt to discuss core concepts that are important for understanding attack surfaces later in this blog series.

API Security

OAuth 2.0 and OIDC implementation

Understanding the core protocols of OAuth and OIDC is key before exploring various authorization and authentication workflows. OAuth, an open standard for delegated authorization in RESTful APIs, operates over HTTPS, enabling secure, delegated access using access tokens instead of credentials. These tokens, cryptographically signed by the Identity Provider (IdP), establish a trust relationship, allowing applications to grant user access. The typical OAuth workflow involves user access requests, user authentication, proof-of-authorization code delivery, and token issuance for API requests. Access tokens are verified with the IdP to determine access scope.

OIDC (API endpoints) builds upon OAuth for authentication, introducing identity-focused scopes and an ID token in addition to the access token. This token, a JSON Web Token (JWT), contains identity information and a signature, crucial for SSO functionality and user authentication. Okta, as a certified OIDC provider, leverages these endpoints, especially when acting as an authorization server for Service Providers (SPs).

Demonstrating Proof-of-Possession (DPoP) is crucial in this context, enhancing security by preventing misuse of stolen tokens through an application-level mechanism. It involves a public/private key pair where the public key, embedded in a JWT header, is sent to the authorization server. The server binds this public key to the access token, ensuring secure communication primarily between the user’s browser and the IdP or SP.

Tokens and API keys in Okta’s API Access Management play a vital role, acting as digital credentials post-user authentication. They are transmitted securely via HTTPS and have a limited lifespan, contributing to a scalable, stateless architecture.

Lastly, understanding End-to-End Encryption (E2EE) is essential. E2EE ensures that data is encrypted at its origin and decrypted only by the intended recipient, maintaining security and privacy across the ecosystem. This encryption, using asymmetric cryptography, is a default feature within Okta’s APIs, safeguarding data across applications, browsers, IdPs, and SPs.

RESTful API and CRUD

Okta's RESTful API adheres to a standardized interface design, ensuring uniformity and predictability across all interactions. This design philosophy facilitates CRUD (Create, Read, Update, Delete) operations, making it intuitive for developers to work with Okta's API. Each API endpoint corresponds to standard HTTP methods — POST for creation, GET for reading, PUT for updating, and DELETE for removing resources. This alignment with HTTP standards simplifies integration and reduces the learning curve for new developers.

A key feature of Okta providing a RESTful API is its statelessness — each request from client to server must contain all the information needed to understand and complete the request, independent of any previous requests. This approach enhances scalability, as it allows the server to quickly free resources and not retain session information between requests. The stateless nature of the API facilitates easier load balancing and redundancy, essential for maintaining high availability and performance even as demand scales.

SCIM

SCIM (System for Cross-domain Identity Management) is an open standard that automates user identity management across various cloud-based applications and services. Integral to Okta's API Access Management, SCIM ensures seamless, secure user data exchange between Okta and external systems. It standardizes identity information, which is essential for organizations using multiple applications, reducing complexity and manual error risks.

Within Okta, SCIM’s role extends to comprehensive user and group management, handling essential attributes like usernames, emails, and group memberships. These are key for access control and authorization. Okta’s SCIM implementation is customizable, accommodating the diverse identity management needs of different systems. This adaptability streamlines identity management processes, making them more automated, efficient, and reliable - crucial for effective API access management.

More information on SCIM can be found in RFC 7644 or by Okta.

Access policies

Okta's access policies play a critical role in managing access to applications and APIs. They can be customized based on user/group membership, device, location, or time, and can enforce extra authentication steps for sensitive applications. These policies, stored as JSON in Okta, allow for:

• Creating complex authorization rules.
• Specifying additional authentication levels for Okta applications.
• Managing user access and modifying access token scopes with inline hooks.

Key Policy Types in Okta include:

• Sign-On Policies: Control app access with IF/THEN rules based on context, like IP address.
• Global Session Policy: Manages access to Okta, including factor challenges and session duration.
• Authentication Policy: Sets extra authentication requirements for each application.
• Password Policy: Defines password requirements and recovery operations.
• Authenticator Enrollment Policy: Governs multifactor authentication method enrollment.

Policy effectiveness hinges on their sequential evaluation, applying configurations when specified conditions are met. The evaluation varies between the AuthN and Identity Engine pipelines, with the latter considering both global session and specific authentication policies.

Additionally, Network Zones in Okta enhances access control by managing it based on user connection sources. These zones, allowing for configurations based on IP addresses and geolocations, integrate with access policies to enforce varied authentication requirements based on network origin. This integration bolsters security and aids in monitoring and threat assessment.

Session management

In web-based interactions involving Identity Providers (IdPs) like Okta and Service Providers (SPs), the concept of a session is central to the user experience and security framework. A session is typically initiated when an end-user starts an interaction with an IdP or SP via a web browser, whether this interaction is intentional or inadvertent.

Technically, a session represents a state of interaction between the user and the web service. Unlike a single request-response communication, a session persists over time, maintaining the user's state and context across multiple interactions. This persistence is crucial, as it allows the user to interact with web services without needing to authenticate for each action or request after the initial login.

A session can hold a variety of important data, which is essential for maintaining the state and context of the user's interactions. This includes, but is not limited to:

Cookies: These are used to store session identifiers and other user-specific information, allowing the web service to recognize the user across different requests.

Tokens: Including access, refresh, and ID tokens, these are critical for authenticating and authorizing the user, and for maintaining the security of their interactions with the web service.

User Preferences and Settings: Customizations or preferences set by the user during their interaction.

Session Expiration Data: Information about when the session will expire or needs to be refreshed. This is vital for security, ensuring that sessions don’t remain active indefinitely, which could pose a security risk.

The management of sessions, particularly their creation, maintenance, and timely expiration is a crucial aspect of web-based services. Effective session management ensures a balance between user convenience — by reducing the need for repeated logins — and security — by minimizing the risk of unauthorized access through abandoned or excessively long-lived sessions. In the interactions between the end-user, IdP, and SP, sessions facilitate a seamless yet secure flow of requests and responses, underpinning the overall security and usability of the service.

Session initialization and authentication:

Okta manages user sessions beginning with the IdP session, which is established when a user successfully authenticates using their credentials, and potentially multi-factor authentication (MFA). This IdP session is key to accessing various applications integrated into an organization's Okta environment. For instance, an HTTP POST request to Okta's /api/v1/authn endpoint initiates this session by validating the user's credentials. In addition, the Sessions endpoint API can help facilitate creation and management at /api/v1/sessions.

Okta primarily uses cookies for session management, specifically in the context of identity provider (IdP) sessions. These cookies are crucial for maintaining the session state and user context across HTTP requests within the Okta environment. A typical session cookie retrieval for the end-user’s browser goes as follows:

1. IdP or SP-initiated application access request
2. Authentication request either via OIDC or SAML
3. After successful credential validation, a session token is returned
4. Redirection to OIDC endpoint, session redirection, or application embed link for session cookie

As detailed, when a user successfully authenticates, Okta ultimately sets a session cookie in the user’s browser. This cookie is then used to track the user session, allowing for seamless interaction with various applications without the need for re-authentication.

Tokens vs cookies:

While Okta utilizes tokens like ID and access tokens for API access and authorization, these tokens serve a different purpose from session cookies. Tokens are typically used in API interactions and are not responsible for maintaining the user’s session state. In contrast, session cookies are specifically designed for maintaining session continuity within the web browser, making them essential for web-based SSO and session management within Okta.

Session tokens are similar to client-side secrets, just like authorization codes during authorization requests. These secrets, along with the correct requests to specific API endpoints can allow an end-user, or adversary, to obtain a session cookie or access token which can then be used to make authenticated/authorized requests on behalf of the user. This should warrant increased security measures for session management and monitoring.

Single sign-on (SSO):

SSO is a critical feature in Okta's session management, allowing users to access multiple applications with a single set of credentials. This is achieved through protocols like SAML and OIDC, where an HTTP(S) request to the SAML endpoint, for instance, facilitates user authentication and grants access across different applications without the need for repeated logins.

In Single Sign-On (SSO) scenarios, Okta’s session cookies play a vital role. Once a user is authenticated and a session is established, the same session cookie facilitates access to multiple applications within the SSO framework by bundled with every service provider request. This eliminates the need for the user to log in separately to each application, streamlining the user experience.

Session termination:

Terminating a session in Okta can occur due to expiration. This can also occur from a user, SP, or IdP-initiated sign-out. An HTTP GET request to Okta's /api/v1/sessions/me endpoint can be used to terminate the user’s session. In the case of SSO, this termination can trigger a single logout (SLO), ending sessions across all accessed applications.

Application sessions and additional controls:

Application sessions are specific to the application a user accesses post-authentication with the IdP. Okta allows fine-grained control over these sessions, including different expiration policies for privileged versus non-privileged applications. Additionally, administrators can implement policies for single logout (SLO) or local logout to further manage session lifecycles.

Understanding the mechanics of session initiation, management, and termination, as well as the role of tokens and cookies, is foundational for exploring deeper security topics. This knowledge is crucial when delving into areas like attack analysis and session hijacking, which will be discussed in later parts of this blog series.

More information on sessions can be found in Session management with Okta or Sessions for Developers.

Tenants

In the SaaS realm, a tenant is a distinct instance of software and infrastructure serving a specific user group. In Okta's multi-tenant platform, this concept is key for configuring access control. Tenants can represent various groups, from internal employees to external contractors, each requiring unique access to applications. This is managed through Okta, serving as the IdP.

Tenants are versatile within Okta: they can be tailored based on security policies, user groups, roles, and profiles, allowing them to operate independently within the organization. This independence is crucial in multi-tenant environments, where distinct tenants are segregated based on factors like roles, data privacy, and regulatory requirements. Such setups are common in Okta, enabling users to manage diverse access needs efficiently.

In multi-org environments, Okta facilitates tenants across separate organizations through its UD. The configuration of each tenant is influenced by various factors including cost, performance, and data residency, with user types and profiles forming the basis of tenant setup. Additionally, features like delegated admin support and DNS customization for post-sign-in redirects are instrumental in managing tenant access.

Understanding the nuances of tenant configuration in Okta is vital, not only for effective administration but also for comprehending potential security challenges, such as the risk of poisoned tenants.

Authorization workflow

As we discussed earlier, Okta - being an IdP - provides an authorization server as part of its services. It is critical to understand the authorization workflow that happens on the front and back-end channels. For this discussion and examples, we will use the client (end-user), authorization server (Okta), and SP (application server) as the actors involved.

OAuth 2.0 and OIDC protocols

High-level overview of OAuth

OAuth 2.0, defined in RFC 6749, is a protocol for authorization. It enables third-party applications to gain limited access approved by the end-user or resource owner. Operating over HTTPS, it grants access tokens to authorize users, devices, APIs, servers, and applications.

Key OAuth terminology:

Scopes: Define the permissions granted within an access token. They represent session permissions for each interaction with a resource server.

Consent: A process where end users or clients agree or disagree with the permissions (scopes) requested by a client application. For example, a consent screen in Google Workspace.

Tokens: Includes access tokens for resource access and refresh tokens for obtaining new access tokens without re-authorizing.

Grants: Data sent to the authorization server to receive an access token, like an authorization code granted post-authentication.

Clients: In OAuth, clients are either 'confidential', able to securely store credentials, or 'public', which cannot.

Authorization Server: Mints OIDC and OAuth tokens and applies access policies, each with a unique URI and signing key.

Authorization Endpoint: An API endpoint (/oauth/authorize) for user interaction and authorization.

Token Endpoint: An API endpoint (/oauth/token) for clients to obtain access or refresh tokens, typically requiring a grant type like authorization code.

Resource Server (or Service Provider, SP): Provides services to authenticated users, requiring an access token.

Front-end Channel: Communication between the user’s browser and the authorization or resource server.

Back-end Channel: Machine-to-machine communication, such as between resource and authorization servers.

This streamlined overview covers the essentials of OAuth in the Okta ecosystem, focusing on its function, key terms, and components.

High-level overview of OIDC

At the beginning of this blog, we also discussed how OIDC is an identity authentication protocol that sits on top of the OAuth authorization framework. While OAuth provides authorization, it has no current mechanism for authentication, thus where OIDC protocol comes in handy. The identity of the authenticated user is often called the resource owner.

The OIDC connect flow looks similar to the OAuth flow, however during the initial HTTPS request, scope=openid is added to be used so that not only an access token is returned from the authorization server but an ID token as well.

The ID token is formatted as a JSON Web Token (JWT) so that the client can extract information about the identity. This is unlike the access token, which the client passes to the resource server every time access is required. Data such as expiration, issuer, signature, email, and more can be found inside the JWT - these are also known as claims.

Authorization code flow

Step 1 - Initial authorization request:

The authorization code flow is initiated when the client sends an HTTP GET request to Okta’s authorization endpoint. This request is crucial in establishing the initial part of the OAuth 2.0 authorization framework.

Here’s a breakdown of the request components:

• Endpoint: The request is directed to /oauth2/default/v1/authorize, which is Okta’s authorization endpoint
• Parameters:
  • response_type=code: This parameter specified that the application is initiating an authorization code grant type flow.
  • client_id: The unique identifier for the client application registered with Okta.
  • redirect_uri: The URL to which Okta will send the authorization code.
  • scope: Defines the level of access the application is requesting.

Example Request:

GET /oauth2/default/v1/authorize?response_type=code \ 
&client_id=CLIENT_ID&redirect_uri=REDIRECT_URI&scope=SCOPE

Step 2 - User authentication and consent:

Once the request is made, the user is prompted to authenticate with Okta and give consent for the requested scopes. This step is fundamental for user verification and to ensure that the user is informed about the type of access being granted to the application.

Step 3 - Authorization code reception:

Post authentication and consent, Okta responds to the client with an authorization code. This code is short-lived and is exchanged for a more permanent secret to make further requests - an access token.

Example token exchange request:

POST /oauth2/default/v1/token
Content-Type: application/x-www-form-urlencoded

grant_type=authorization_code&
code=AUTHORIZATION_CODE&
redirect_uri=REDIRECT_URI&
client_id=CLIENT_ID&
client_secret=CLIENT_SECRET

Step 4 - Redirect URIs and client authentication

Redirect URIs play a pivotal role in the security of the OAuth 2.0 flow. They are pre-registered URLs to which Okta sends the authorization code. The integrity of these URIs is paramount, as they ensure that the response is only sent to the authorized client.

The client application is authenticated at the token endpoint, usually by providing the client_id and client_secret. This step is crucial to verify the identity of the client application and prevent unauthorized access.

Step 5 - Token exchange

In the final step, the client makes an HTTP POST request to Okta’s token endpoint, exchanging the authorization code for an access token. This access token is then used to make API requests on behalf of the user.

The inclusion of client credentials (client ID and client secret) in this request is a critical security measure, ensuring that the token is only issued to the legitimate client.

Access tokens and scopes

An access token is a compact code carrying extensive data about a user and their permissions. It serves as a digital key, facilitating communication between a server and a user's device. Commonly used in various websites, access tokens enable functionalities like logging in through one website (like Facebook) to access another (like Salesforce).

Composition of an access token:

An access token typically comprises three distinct parts, each serving a specific purpose:

• Header: This section contains metadata about the token, including the type of token and the algorithm used for encryption.
• Payload (claims): The core of the token, includes user-related information, permissions, group memberships, and expiration details. The payload dictates whether a user can access a specific resource, depending on the permissions granted within it. Developers can embed custom data in the payload, allowing for versatile applications, such as a single token granting access to multiple APIs.
• Signature: A hashed verification segment that confirms the token's authenticity. This makes the token secure and challenging to tamper with or replicate.

A common format for access tokens JWT as we previously discussed, which is concise yet securely encodes all necessary information.

Scopes and permissions:

Scopes in OAuth 2.0 are parameters that define the level and type of access the client requests. Each scope translates into specific permissions granted to the access token. For instance, a scope of email would grant the client application access to the user's email address. The granularity of scopes allows for precise control over what the client can and cannot do with the access token, adhering to the principle of least privilege.

Token lifespan and refresh tokens:

Access tokens are inherently short-lived for security reasons, reducing the window of opportunity for token misuse in case of unintended disclosure. Okta allows customization of token lifespans to suit different security postures. Once an access token expires, it can no longer be used to access resources.

Refresh tokens, where employed, serve to extend the session without requiring the user to authenticate again. A refresh token can be exchanged for a new access token, thus maintaining the user's access continuity to the application. The use of refresh tokens is pivotal in applications where the user remains logged in for extended periods.

Token storage:

Regarding token storage, browser-based applications such as those utilizing services like Okta, are vital secure storage of access tokens is a critical aspect of user session management. These tokens are typically stored using one of several methods: browser in-memory storage, session cookies, or browser local/session storage. In-memory storage, preferred for its strong defense against XSS attacks, holds the token within the JavaScript memory space of the application, although it loses the token upon page refresh or closure. Session cookies offer enhanced security by being inaccessible to JavaScript, thereby reducing XSS vulnerabilities, but require careful implementation to avoid CSRF attacks. Local and session storage options, while convenient, are generally less recommended for sensitive data like access tokens due to their susceptibility to XSS attacks. The choice of storage method will depend on the application where a traditional web page, mobile device, or single-page app is being used.

Security and expiration:

The security of access tokens is of paramount importance in safeguarding user authentication and authorization processes, especially during their transmission over the internet. Encrypting these tokens is crucial, as it ensures that their contents remain confidential and impervious to unauthorized access. Equally important is the use of secure communication channels, notably HTTPS, to prevent the interception and compromise of tokens in transit. Furthermore, the signature component of a token, particularly in JWTs, plays a vital role in verifying its authenticity and integrity. This signature confirms that the token has not been altered and is genuinely issued by a trusted authority, thus preventing the risks associated with token forgery and replay attacks.

Access tokens are inherently designed with expiration mechanisms, a strategic choice to mitigate the risks associated with token theft or misuse. This finite lifespan of tokens necessitates regular renewal, typically managed through refresh tokens, thereby ensuring active session management and reducing opportunities for unauthorized use. The storage and handling of these tokens in client applications also significantly impact their overall security. Secure storage methods, such as in-memory or encrypted cookies, alongside careful management of token renewal processes, are essential to prevent unauthorized access and maintain the robustness of user sessions and access controls.

Authentication workflow

Authentication vs authorization

Before we dive into authentication in Okta, we should take a moment to understand the difference between authentication and authorization. To put it simply, authentication is providing evidence to prove identity, whereas authorization is about permissions and privileges once access is granted.

As we discussed throughout this blog, the Identity Engine and UD are critical to identity management in Okta. As a recap, the Identity Engine is used for enrolling, authentications, and authorizing users. The UD is used as the main directory service in Okta that contains users, groups, profiles, and policies, also serving as the source of truth for user data. The UD can be synchronized with other directory services such as AD or LDAP through the Okta endpoint agent.

Identity management can be managed via Okta or through an external IdP, such as Google Workspace. Essentially, when access to an application is requested, redirection to the authorization server’s endpoint APIs for authentication are generated to provide proof of identity.

Below are the main authentication protocols between the end user, resource server, and authorization server:

• OIDC: Authentication protocol that sits on top of the OAuth authorization framework. Workflow requires an ID token (JWT) to be obtained during an access token request.
• SAML: Open standard protocol formatted in XML that facilitates user identity data exchange between SPs and IdPs.

Within Okta, there is plenty of flexibility and customization regarding authentication. Basic authentication is supported where simple username and password schemes are used over HTTP with additional parameters and configurations.

SAML in authentication

As previously stated, SAML is a login standard that helps facilitate user access to applications based on HTTP(s) requests and sessions asynchronously. Over time the use of basic credentials for each application quickly became a challenge and thus federated identity was introduced to allow identity authentication across different SPs, facilitated by the identity providers.

SAML is primarily a web-based authentication mechanism as it relies on a flow of traffic between the end user, IdP, and SP. The SAML authentication flow can either be IdP or SP initiated depending on where the end user visits first for application access.

The SAML request is typically generated by the SP whereas the SAML response is generated by the IdP. The response contains the SAML assertion, which contains information about the authenticated user’s identity and a signed signature by the IdP.

It is important to note that during the SAML workflow, the IdP and SP typically never communicate directly, but instead rely on the end user’s browser for redirections. Typically, the SP trusts the IdP and thus the identity data forwarded through the user’s web browser to the SP is trusted in access is granted to the application requested.

In step 5 from the diagram above, the SAML assertion would be sent as part of this response after the user has authenticated with the IdP. Remember that the assertion is in XML format and can be quite extensive as it contains identity information for the SP to parse and rely on for the end user’s identity verification. Generic examples of SAML assertions are provided by OneLogin. Auth0 also provides a decoder and parser for these examples as well which is shown in the image below.

IdP vs SP responsibilities

When discussing the roles and responsibilities of the SP and IdP, keep in mind that the SP is meant to provide access to applications for the end user, whereas the IdP provides authentication and authorization. The SP and IdP are typically set up to trust each other with their designated responsibilities. Depending on the end user, workflows for authentication and authorization can be SP or IdP initiated where RESTful API endpoints are typically depended on for each workflow. For authentication, requests and responses are sent from the IdP and SP but often proxied through the end user’s browser.

Although Okta is mainly an IdP and provides authentication and authorization services, it can also be used as an SP. Previously we discussed how Okta’s integration network allows for various 3rd-party applications to be connected and accessible to users through their dashboard. We also explained how authentication workflows can be SP initiated, meaning users could visit their Okta dashboard to request access to an application. At the same time, a 3rd-party IdP could be established such as Google Workspace or Azure AD which would handle the authentication and authorization of the user. If the user were to request access with this type of setup, Okta would then redirect the user to Azure AD for authentication.

Single-factor vs multi-factor authentication

Single-factor authentication (SFA) is the simplest form of authentication, requiring a user to supply one credential object for authentication. Commonly, users are familiar with password-based authentication methods where a username and password are supplied to validate themselves. This of course has security implications if the credentials used are stolen as they can be used by an adversary to login and access the same resources.

Multifactor authentication (MFA) is similar to SFA, except it requires two or more types of credentials or evidence to be supplied for authentication, typically in sequence. For example, a password-based credential may be supplied and once verified by the IdP, then requested by an OTP be supplied by a mobile device authenticator application, SMS message, email, and others. The common types of authentication factors are something that the user knows, possesses, or is inherent. This also increases the complexity to adversaries based on randomized string generation for OTPs and MFA token expirations.

Okta enables other types of authentication methods such as passwordless, risk-based, biometric, transaction, and others. A full list of authentication methods and descriptions can be found here.

Every application or integration added to the Okta organization has an authentication policy, which verifies conditions for users who attempt to access each application. Authentication policies can also help enforce factor requirements based on these conditions where the UD and user profile are used to analyze information about the user. Authentication policies can be set globally for applications and users or can be more granular if set at the application level where specific user conditions are met. Authentication policies can be updated, cloned, preset, and merged if duplicate policies. Rules that define these granular conditions can be applied to these authentication policies with the Okta Expression Language (EL).

Client-side and server-side communications

Understanding the distinction between front-end (user-browser interactions) and back-end (server-to-server communications) is crucial in web-based authentication systems. Front-end interactions typically involve user interfaces and actions, while back-end channels handle critical exchanges like SAML assertions or OAuth tokens, crucial for secure authentication.

In Okta's framework, the interplay between browser and server is key for security and user experience. When a user logs in via Okta, the browser first authenticates with Okta, which then sends back the necessary tokens. These are forwarded to the application server which validates them with Okta, ensuring a secure, behind-the-scenes token exchange.

Okta’s token management is marked by stringent security. Issued tokens like ID and access tokens are securely exchanged among the user’s browser, Okta, and application servers. Protocols like HTTPS and OAuth 2.0 safeguard these transmissions. Features like token rotation and automatic revocation further bolster security, preventing unauthorized access.

Integrating Okta into an application reshapes its design and security. This offloads significant security responsibilities, allowing developers to focus on core functions. Such integration leads to a modular architecture, where authentication services are separate from application logic.

결론

We’ve unraveled the complexities of Okta’s architecture and services, providing insights into its role as a leader in modern authentication and authorization. With the platform’s utilization of protocols like OAuth, OIDC, and SAML, Okta stands at the forefront of scalable, integrated solutions, seamlessly working with platforms such as Azure AD and Google Workspace.

Okta's SaaS design, featuring a RESTful API, makes it a versatile Identity Provider (IdP) and Service Provider (SP). Yet, its popularity also brings potential security vulnerabilities. For cybersecurity professionals, it’s crucial to grasp Okta’s complexities to stay ahead of evolving threats. This introduction sets the stage for upcoming deeper analyses of Okta's attack surface, the setup of a threat detection lab, and the exploration of common attacks.

Armed with this knowledge, you’re now better equipped to analyze, understand, and mitigate the evolving cybersecurity challenges associated with Okta’s ecosystem.