SSO (single sign-on) lets your employees sign in once and open all their connected work applications without logging in again for each one. It saves time, and when it's set up properly it also tightens security.

SSO ran quietly inside large-company IT for years and is now standard in most Microsoft 365 and cloud-first environments. Here is what it means and why it matters for a small or midsize business.

What does SSO stand for?

Single Sign-On. A user authenticates once, typically at the start of the workday or when they open their laptop, and then reaches every connected application without another login prompt.

The simple way to think about it

Without SSO, starting the workday looks like this: sign into Windows, then email, then the practice management system, the billing platform, the HR portal and the file-sharing tool. Each has its own username and password, and some have their own MFA prompt. By mid-morning your staff has typed credentials six times and forgotten two of them.

With SSO, they open the laptop, authenticate once (a password plus a multi-factor authentication (MFA) prompt), and the connected applications open without another login. That first sign-in is trusted across the connected applications for the rest of the session.

Think of it as one well-guarded master key instead of a ring of seventeen keys for seventeen doors.

How SSO works

SSO relies on identity standards, most commonly SAML, OAuth and OpenID Connect, that let applications hand the job of verifying a user to a central identity provider (IdP) instead of each managing its own logins.

For most businesses, the identity provider is Microsoft Entra ID (formerly Azure Active Directory). When a user opens Teams, SharePoint, a third-party cloud tool or a line-of-business application, that application checks with Entra ID whether the user is already signed in. If so, they get in. If not, they sign in with Microsoft first.

The identity provider also enforces your security policies in one place: MFA requirements, conditional access rules, device compliance checks and session timeouts.

Why SSO improves security

People sometimes ask whether one sign-in is riskier than many. In practice it usually isn't, for a few reasons:

• Fewer passwords means better passwords. People juggling many credentials reuse them, write them down or pick weak variations. SSO shrinks the number of passwords to protect.
• MFA is applied consistently. Enforce MFA at the identity provider and it covers every connected application, instead of being configured app by app and often left incomplete.
• Offboarding is faster and more complete. When an employee leaves, disabling their account and revoking active sessions in the identity provider cuts off access to every connected application. Apps that aren't connected to SSO still need to be handled separately, so a short offboarding checklist remains important.
• Sign-in activity is in one place. Unusual locations, impossible travel and repeated failed attempts all show up in one log instead of a dozen.

SSO and compliance

HIPAA, PCI DSS and most other frameworks call for access controls, logging of sign-in activity and prompt removal of access when someone leaves. SSO makes each of these easier to put in place and easier to show an auditor. A central identity provider with a complete sign-in log is far easier to document than application-specific accounts managed inconsistently. For more, see how we help with compliance requirements like HIPAA, PCI and SOC 2.

How NerdSquad sets up SSO for clients

NerdSquad Managed IT Services is a Managed Service Provider (MSP). For most business clients, SSO means configuring Microsoft Entra ID as the identity provider and connecting business-critical applications to it: Microsoft 365 applications natively and third-party applications through SAML or OAuth. This work is part of our managed IT services and Microsoft 365 support. We pair SSO with MFA and conditional access policies as part of a Zero Trust approach to identity, and it is one of the most useful changes we make in a new client environment.

Talk to NerdSquad

Already a client? Call (239) 465-0079 or submit a ticket. If something is down, call so we can start right away.

Not a client yet? NerdSquad Managed IT Services is a Managed Service Provider (MSP) based in Naples, Florida. We support businesses onsite across Southwest Florida and remotely nationwide. Book a discovery call or call (239) 465-0079.

Related: Microsoft 365 support