What is single sign-on (SSO)?

Picture this: You start your workday by logging into your computer, then spend the next 15 minutes entering different usernames and passwords to access your email, CRM, marketing automation tool, and project management software. Sound familiar? This tedious process not only eats into your productivity but also increases the risk of forgotten passwords and security breaches. 

That's where single sign-on (SSO) comes in. It provides a streamlined solution to this daily challenge, allowing users to access different applications and services with just one set of credentials. SSO not only enhances user experience by eliminating password fatigue but also bolsters security by reducing the number of entry points for potential attackers.

This article walks you through the concept of SSO, exploring how single sign-on works, its types, benefits, drawbacks, and best practices for implementation.

What is SSO?

SSO is an authentication method that allows users to access multiple applications with a single set of login credentials. Instead of managing separate usernames and passwords for each application, users can sign in once and seamlessly navigate between different services.

For example, when you log into your Google account, you gain access to Gmail, Google Drive, Google Calendar, and other Google services without having to authenticate again for each one. That's SSO authentication in action.

How does SSO work?

SSO systems rely on identity providers (IdPs) to manage user identities and handle authentication. An IdP is a trusted third-party service that stores and manages digital identities. Some popular identity providers include Google, Auth0, Microsoft Azure Active Directory, and Okta. 

When a user attempts to access an application within an SSO ecosystem, the process typically unfolds as follows:

1. The user signs in with their single set of login credentials (username and password) into the SSO login portal.
2. The SSO service forwards these credentials to the IdP, which authenticates them against its centralized identity database.
3. Upon successful authentication, the IdP issues an authentication token that confirms the user's identity. This SSO token serves as a digital passport, allowing the user to access various apps without re-entering their credentials.
4. The SSO system shares this token with the applications and services within its network, granting the user seamless access to all authorized resources.

Cut through the chaos of multiple logins

See Rippling SSO

Benefits of SSO

Single sign-on solutions offer a range of benefits to enhance both user experience and organizational efficiency and they include:

Improved user experience

One of the primary benefits of SSO is the improved user experience it offers. By eliminating the need for users to remember and enter multiple sets of credentials, SSO makes accessing apps and services much more convenient. This streamlined login process can lead to increased productivity and reduced user frustration.

Enhanced security

While it may seem counterintuitive, SSO can actually enhance security in several ways:

• Users are less likely to use weak or reused passwords since they only need to remember one set of credentials.
• IT administrators can enforce strong password management policies and multi-factor authentication more easily with SSO.
• Centralized authentication makes it easier to monitor and detect suspicious login activity.

However, it's important to note that SSO is only as secure as the underlying identity management system. Organizations must implement robust security measures to protect user credentials and prevent unauthorized access.

Reduced IT costs

Password-related issues can be a significant drain on IT resources. SSO centralizes authentication, reducing the frequency of password resets and account lockouts. This centralization lightens the load on IT help desks, potentially lowering operational costs associated with managing user access.

Increased productivity

Time spent logging into various applications adds up. SSO reduces these login delays, allowing employees to access their tools more quickly. This streamlined process means less time wrestling with passwords and more time focused on important tasks.

Simplified access management

Managing user access across multiple systems can be complex. SSO provides a central point for controlling user permissions. This approach allows IT administrators to efficiently manage access rights, ensuring employees have appropriate system access based on their roles.

Drawbacks of SSO

Despite its many benefits, SSO is not without its limitations and potential risks. As with any technology, it's important to understand the full picture before implementation. Here are some important considerations and potential downsides to be aware of when adopting SSO:

Single point of vulnerability

One significant concern with SSO is that it can create a single point of vulnerability. If the SSO system goes down or is compromised, users may be unable to access any of the connected applications or services. Moreover, if a user's SSO credentials are compromised, an attacker could potentially gain access to all connected systems. To mitigate these risks, organizations must ensure their SSO solution is reliable, scalable, and secure.

Compatibility issues

Not all applications and services may be compatible with an organization's chosen SSO provider. This can lead to integration challenges and require additional effort to incorporate these systems into the SSO platform. Organizations should carefully evaluate their existing technology stack and choose an SSO solution that offers broad compatibility and easy integration.

Initial implementation complexity 

While SSO can simplify user access in the long run, the initial implementation can be complex and time-consuming. It often requires significant planning, configuration, and testing to ensure smooth integration across all systems. Organizations need to consider the resources and expertise required for successful SSO deployment.

Types of SSO solutions

SSO solutions come in various forms, each tailored to specific organizational needs and use cases. Let's explore some key types:

Enterprise SSO

Enterprise SSO is designed for use within a single organization. It allows employees to access multiple internal applications and services with a single set of credentials, usually managed by the organization's IT department. Enterprise SSO solutions are often integrated with the organization's existing identity management system, such as Active Directory or LDAP.

Web SSO

Web SSO enables users to access multiple web applications with a single set of credentials. This type of SSO is often used by businesses to provide their customers with a seamless login experience across various web services.

Federated identity management

Federated identity management (FIM) extends SSO beyond a single organization, allowing users to access resources across multiple trusted business partners. In a federated system, the user's identity is managed by their home organization (the identity provider), and access to resources at partner organizations (service providers) is granted based on trust relationships established between the parties.

Key features of SSO solutions

While features may vary between providers, the most effective SSO solutions typically include several core capabilities. When evaluating SSO options, look for these essential features:

Multi-factor authentication

Multi-factor authentication (MFA) is a security mechanism that requires users to provide additional proof of identity beyond a username and password. Common MFA methods include:

• SMS or voice-based one-time passcodes
• Hardware or software-based security tokens
• Biometric factors (e.g., fingerprint, facial recognition)

Implementing MFA alongside SSO adds an extra layer of security, making it much harder for attackers to gain unauthorized access even if they obtain a user's primary credentials.

User provisioning and deprovisioning

SSO solutions often include user provisioning and deprovisioning capabilities, which automate the process of creating, updating, and removing user accounts across connected applications and services. This ensures that users have access to the resources they need while maintaining security and compliance.

Access management and governance

Advanced SSO solutions offer granular access management and governance features, allowing administrators to define and enforce access policies based on user roles, groups, and other attributes. This helps organizations maintain tight control over who can access specific resources and ensures that access permissions are granted and revoked in a timely manner.

Integration with identity providers

SSO solutions should seamlessly integrate with popular identity providers, such as Active Directory, LDAP, and cloud-based IdPs like Google and Azure AD. This allows organizations to leverage their existing identity management infrastructure and simplifies the implementation and management of SSO.

Best practices for implementing SSO

Ensuring a robust and effective SSO system involves more than just technology. Here are key practices to guide your implementation journey:

• Choose a robust SSO solution: Select an SSO solution that is compatible with your existing systems, scalable to accommodate future growth, compliant with relevant security standards, and offers advanced security features like MFA.
• Conduct regular security audits: Perform periodic security audits of your SSO system to identify and address vulnerabilities. This may include penetration testing, code reviews, access control audits, and monitoring login activity for suspicious behavior.
• Educate employees: Provide regular training and awareness programs to help employees understand the importance of strong passwords, how to identify and report suspicious activity, and best practices for using SSO and MFA.
• Implement a comprehensive incident response plan: Establish a well-defined incident response plan that outlines the steps to be taken in the event of a suspected security breach, including identifying and containing the incident, investigating the cause and scope, notifying affected parties, and remediating the vulnerability.
• Keep SSO software up-to-date: Regularly update your SSO software to ensure that you have the latest security patches and features. Stay informed about new threats and vulnerabilities, and take proactive steps to mitigate them.
• Monitor and log user activity: Continuously monitor SSO system and user logs to detect potential security incidents. Implement alerting mechanisms to notify administrators of suspicious behavior and enable rapid response to threats.

Common SSO protocols and standards

SSO relies on various protocols to enable secure authentication across systems. Let's explore these key protocols and standards:

SAML

Security assertion markup language (SAML) is an open standard that enables SSO by allowing identity providers to pass authentication and authorization information to service providers in the form of XML-based assertions.

OAuth

OAuth is an open standard for access delegation that allows users to grant third-party applications limited access to their resources without sharing their credentials. While OAuth is primarily used for authorization, it can also be used to enable SSO when combined with other authentication protocols like OpenID Connect.

OpenID connect

OpenID connect (OIDC) is an authentication layer built on top of OAuth 2.0. It enables clients to verify the identity of the end-user and obtain basic profile information. OIDC is commonly used in web and mobile applications for SSO and user identity management.

Kerberos

Kerberos is a network authentication protocol that uses tickets to allow nodes on a network to securely prove their identity. It is primarily used in Windows environments and is the foundation for Microsoft's Active Directory SSO.

JSON web tokens (JWT)

JSON web tokens (JWT) is an open standard that defines a compact and self-contained way of securely transmitting information between parties as a JSON object. JWTs can be used as a means of authentication in SSO systems, particularly in web and mobile applications.

Cut through the chaos of multiple logins

See Rippling SSO

SSO vs. Other authentication methods

SSO vs. Active Directory

Active Directory (AD) is a Microsoft directory service used for managing identities and access within a Windows domain network. While AD can be used as an identity provider for SSO, it is primarily designed for managing on-premises resources. SSO solutions, on the other hand, are typically cloud-based and can integrate with a variety of identity providers, including AD.

SSO vs. LDAP

Lightweight Directory Access Protocol (LDAP) is an open protocol used for accessing and maintaining distributed directory information services. Like AD, LDAP can be used as an identity provider for SSO. However, SSO solutions often offer more advanced features and are better suited for managing access to cloud applications and services.

SSO vs. IAM

Identity and access management (IAM) is a broad framework that encompasses various technologies and processes for managing user identities and access permissions. SSO is just one component of an IAM strategy, focusing specifically on authentication. IAM includes additional functionalities such as user provisioning, access governance, and identity lifecycle management.

Frequently asked questions

What is the difference between authentication and authorization? 

Authentication is the process of verifying a user's identity, while authorization determines what resources and actions a user is permitted to access. In an SSO context, authentication typically happens once, but authorization may occur multiple times as the user accesses different applications.

How does SSO handle user provisioning and deprovisioning? 

Many SSO solutions offer automated processes for creating, modifying, and removing user accounts across connected applications and services. This automation helps maintain consistency across systems and reduces the administrative burden on IT teams.

What are the main challenges in implementing SSO? 

Key challenges in implementing SSO include ensuring compatibility with existing systems, managing user accounts effectively, and maintaining the security of the SSO system. Additionally, organizations often face resistance to change from users who are accustomed to their current login methods.

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