What is SSO, and How Does Single Sign-On Work?

Single Sign-On (SSO) is a technology that allows users to access multiple software applications with a single set of login credentials. It eliminates the need for users to remember different login credentials for each application, making it a convenient and time-saving solution for individuals and businesses. In this article, we will discuss what SSO is, how it works, the benefits of using SSO, and the different types of SSO.

What Is SSO?

Single sign-on (SSO) is an authentication method that allows users to securely authenticate with multiple applications and websites using just one set of credentials. With SSO, users only need to sign in once to access all their apps and services, eliminating the need to remember and enter multiple passwords. SSO works based on a trust relationship between the application (service provider) and the identity provider, where tokens containing user information are exchanged for authentication.

Single Sign-On tokens are data or information collected from one system to another during the SSO process. They typically contain user-identifying information, such as an email address or username, and must be digitally signed to ensure they come from a trusted source. SSO solutions can be provided as software as a service (SaaS) and run in the cloud, simplifying access management and improving the user experience.

SSO is considered secure when best practices are followed. It helps protect users by leveraging consistent security policies, automatically identifying and blocking malicious login attempts. Also, it allows for the deployment of additional security tools like multifactor authentication (MFA). Single Sign-On also plays a role in identity access management (IAM), verifying user identities, providing permission levels, and integrating with activity logs and access control tools.

How Does SSO Work?

To understand how Single Sign-On works, you’ll need to understand the concept of federated identity. Federated identity is the sharing of identity attributes across trusted but autonomous systems. When a user is trusted by one system (identity provider), they are automatically granted access to all other systems that have established a trusted relationship with the identity provider.

How it Works:

The user initiates the authentication process by accessing an application or website part of the Single Sign-On system (known as the service provider).
The service provider sends a token containing information about the user (e.g., email address) to the Single Sign-On system (known as the identity provider) as part of an authentication request.
The identity provider checks if the user has already been authenticated. If the user is authenticated, the identity provider grants access to the service provider and skips to step 5.
If the user hasn’t logged in, they are prompted to provide the identity provider with the necessary credentials (e.g., username and password).
Once the identity provider validates the credentials, it returns a token to the service provider, confirming successful authentication.
The token is passed through the user’s browser to the service provider.
The service provider validates the token according to the trust relationship established with the identity provider during the initial configuration.
When the user tries to access a different website or application within the Single Sign-On system, the new website or application must have a similar trust relationship configured with the Single Sign-On solution, and the authentication flow follows the same steps.

SSO Protocols

SSO employs various protocols to enable the authentication and authorization processes. Two commonly used protocols are OpenID Connect and SAML 2.0.

OpenID Connect is built on OAuth 2.0 and provides an identity layer for identification and authorization. It allows the identity provider to share user information with the service provider without revealing the user’s credentials.
SAML (Security Assertion Markup Language) is an XML-based protocol for exchanging authentication and authorization data between parties involved in SSO.

Why Do People Use Single Sign-On?

SSO is widely used in both consumer and enterprise environments for various reasons, with one of the primary reasons people use it is for improved security and compliance. With SSO, users only need to remember and manage one set of credentials, reducing the likelihood of weak or reused passwords. This helps mitigate the risk of password-related hacks and unauthorized access to sensitive information. Single Sign-On can also help organizations meet regulatory compliance requirements, such as Sarbanes-Oxley and HIPAA, by providing effective authentication, access controls, and audit trail capabilities.

Types of SSO

There are different types of Single Sign-On configurations, including:

#1. Service-Provider-Initiated SSO

This is where the Single Sign-On service provider (SP) authenticates the user. The user is presented with one or more external identity providers, and upon successful authentication, the user is returned to the application.

#2. Identity-Provider-Initiated SSO

In this case, a third-party Identity Provider (IdP) is responsible for authentication. The IdP performs authentication and authorization, and upon successful authentication, the user is returned to the application.

Social SSO services like Google, LinkedIn, and Facebook allow users to log in to third-party applications using their social media authentication credentials. While this provides convenience to users, it can also present security risks.

#4. Enterprise SSO

Enterprise Single Sign-On (eSSO) software and services, such as Okta and OneLogin, provide password managers that log users on to target applications by replaying user credentials. This eliminates the need for users to remember multiple passwords.

#5. Business to Business (B2B)

Single Sign-On can simplify packaging applications for enterprise consumption. It supports common enterprise federation scenarios, such as Active Directory (AD), Lightweight Directory Access Protocol (LDAP), Ping, or Security Assertion Markup Language (SAML).

#6. Business to Consumer (B2C) or Customer Identity Access Management (CIAM)

Single Sign-On can provide frictionless access to applications or services for customers. Customers can authenticate through popular social identity providers like Google, Facebook, LinkedIn, Twitter, and Microsoft instead of creating separate accounts for each service.

What Is SSO in Cyber Security?

SSO can enhance cyber security in several ways:

Centralized authentication: With SSO, a centralized authentication server is in charge of managing authentication. This server is responsible for verifying user identities and granting or denying access based on the organization’s access control policies.
Stronger access control: SSO allows organizations to enforce consistent access control policies across all systems and applications. This ensures that users only have access to the resources they are authorized to use.
Multi-Factor Authentication (MFA): SSO can be combined with MFA to provide an additional layer of security. MFA requires users to provide multiple forms of authentication, such as a password and a one-time passcode sent to their mobile device, further reducing the risk of unauthorized access.
Behavioral analytics: Organizations can use behavioral analytics to detect anomalous or suspicious activity that could indicate a compromised account.

What Is an Example of an SSO?

Examples of SSO Integration include:

Google’s implementation for its software products. Once logged in to Gmail, users automatically gain access to other Google products like YouTube, Google Drive, and Google Photos.
Facebook’s SSO, which allows users to log in to third-party applications using their Facebook credentials

What Are the Three Benefits of SSO?

SSO integration offers several benefits:

Users only need to remember and enter one set of credentials, reducing password fatigue and saving time spent on authentication. This can lead to increased productivity and user satisfaction.
SSO allows organizations to enforce strong authentication measures, such as multi-factor authentication (MFA), to reduce the risk of unauthorized access.
Single Sign-On enables organizations to monitor and detect suspicious activity more effectively by tracking user behavior across multiple systems.
With SSO, applications no longer need to manage their authentication systems, reducing the burden on IT teams. This can lead to cost savings and simplified administration.
SSO integration can help organizations meet regulatory compliance requirements by providing secure access control and audit trails

Risks Associated with Using Single Sign-On

Implementing Single Sign-On can be time-consuming and challenging, especially for applications that don’t natively support SSO protocols.
Single Sign-On introduces potential security risks, such as the risk of unauthorized access if a user leaves their machine logged in or the risk of a denial of service attack on the central authentication service.
Not all applications and services may support the same Single Sign-On protocols, requiring additional configuration and customization.
The identity provider becomes a critical component of the Single Sign-On system, and any issues with the identity provider can impact access to all integrated applications and services.

What Are the Technologies Used in SSO?

There are several technologies and protocols used in SSO implementations:

Kerberos: Kerberos-based setup uses user credentials to issue ticket-granting tickets, fetching service tickets for other applications without reentry.
Security Assertion Markup Language (SAML): SAML is an XML standard for user authentication and authorization in secure domains. It also maintains a user directory and a service provider.
Smart card-based SSO: Smart card-based SSO requires end users to use a card for initial login without re-entry of usernames or passwords.
Federated SSO: Trust is established between a Single Sign-On solution and federated infrastructure resources, thus, granting access without password validation. Therefore, users log in to Identity Providers, which provide tokens, tickets, or assertions.

Choosing the Best SSO Authentication Method

The things you should consider before choosing an SSO authentication method are:

Application compatibility: Ensure the SSO method’s compatibility with integrated applications, as some may support specific methods.
Security requirements: SSO methods provide varying security levels, with Kerberos for single-organization authentication and SAML and OAuth for external integration.
User experience: Consider the user experience when choosing an SSO method. Some methods provide a smoother user experience by allowing user authentication using their existing social media or email accounts.
Scalability and growth: Choose an Single Sign-On method to grow with your company and adapt to your changing needs. Some cloud-based SSO solutions can be more scalable and easier to manage than on-premises ones.

What Is SSO in Customer Service?

Several ways implementing SSO integration in customer service can be achieved:

Internal SSO: This SSO integration approach involves using an identity provider within the organization’s network to authenticate users across multiple applications. The organization manages the Single sign-on infrastructure and controls user access.
External SSO: In this approach, an external identity provider is used to authenticate users. Popular social media platforms like Google, LinkedIn, Apple, Twitter, and Facebook offer Single Sign-On services that allow users to log in to third-party applications using their social media credentials.

What is Required for SSO Integration?

For SSO integration, it is crucial to consider several requirements and considerations. These include open standards support, user onboarding, true SSO, availability and disaster recovery, mobile readiness, flexible password rules, advanced authentication, reporting, behavioral analytics, authorization management, and developer support.

Widely-used protocols like SAML should support open standards, while user onboarding should support commonly-used consumer authentication methods. True SSO should basically allow single sign-on, requiring only one username and password to access all apps/sites.

Availability and disaster recovery should be consistently demonstrated. Also, mobile readiness should be supported through protocols like SAML and partnerships with MDM vendors.

Flexible password rules should be enforced, and advanced authentication options should be available, such as multi-factor or adaptive risk-based authentication. Also, reporting should enable organizations to meet compliance requirements and enhance security based on threat data. Behavioral analytics can intelligently adapt and respond to user behavior, while authorization management should be managed through integration with identity providers.

Furthermore, developer support should include APIs and documentation for single sign-on for internal applications and third-party systems. A well-defined identity and access management roadmap are essential for successful implementation. It generally considers objectives, user requirements, architecture design, access control requirements, refinement, and proper licensing.

What Is the Difference Between SSO and Authentication?

Single Sign-On and authentication are different concepts in their purpose and functionality. Authentication is the process of verifying a user’s identity. At the same time, Single Sign-On is a centralized user session and authentication service that enables users to access multiple applications or services with a single set of credentials.

SSO generally enhances the user experience by reducing the need for multiple passwords and login information for different applications. It shares session information across different domains, by the same token, overcoming limitations imposed by the same-origin policy in web browsers. Generally, it focuses on user convenience by enabling access to multiple applications with a single set of credentials, while authentication focuses on verifying the identity of users or devices.

Also, Single Sign-On solutions often use protocols like SAML or OAuth2/OpenID Connect for seamless access to multiple applications, while authentication can involve various protocols and mechanisms depending on the system.

WHAT IS SSO: Definition & How Single Sign-on Works

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What Is SSO?