As cyber insurers and regulators push for better access management, SSO has become a core security control rather than an optional extra. This guide explains how SSO works, the benefits for UK businesses, the costs to expect, and why pairing it with multi-factor authentication (MFA) is essential to safeguard your data and meet insurance requirements.
What is single sign-on (SSO)?
Single sign-on (SSO) is a login method that enables employees to use a single set of credentials to access multiple applications or systems. Instead of remembering separate passwords for email, finance software, and collaboration tools, staff log in once and use that identity across all approved apps.
For businesses, SSO solves two problems at once: it makes life easier for employees and reduces risk for IT teams. Staff face fewer password resets and less frustration, while businesses get central control over accounts, permissions, and security policies.
SSO is now a common feature in workplaces using Microsoft 365, Google Workspace, Salesforce, and other cloud platforms.
How does single sign-on work?
To end users, SSO feels seamless: one login, access everywhere. Behind the scenes, it relies on identity management, encrypted tokens, and trust relationships that bind everything together.
Central authentication service (the identity provider)
At the centre of SSO is an identity provider (IdP). This could be Azure Active Directory, Okta, Ping Identity, or Google Identity. The IdP holds the master credentials and is responsible for authenticating the user. Instead of each app checking the login separately, the IdP becomes the single authority that other systems trust.
Tokens and trust relationships
When authentication succeeds, the IdP issues a digital “token.” This is a cryptographic certificate proving the user’s identity. Connected apps accept this token in place of a new password entry. Because tokens are time-limited and encrypted, they are much harder to forge than passwords. This mechanism enables users to securely switch between apps without re-entering their details.
Standard protocols: SAML, OAuth, and OpenID Connect
SSO depends on industry protocols to pass tokens and authorisation data between systems.
- SAML (Security Assertion Markup Language): Common in enterprise SSO, especially for web apps.
- OAuth 2.0: Widely used for granting secure delegated access, such as logging in with Google.
- OpenID Connect: An identity layer on top of OAuth, now common for modern apps and APIs.
Understanding these standards is crucial for IT teams, as misconfigurations in SAML or OAuth are a frequent cause of data breaches.
Example login flow
A staff member enters their company credentials into Okta. The IdP validates the credentials and applies MFA. It issues a token, which Slack, Salesforce, and Microsoft 365 all accept. The user accesses each tool without needing to enter an additional password.
For IT, this centralises oversight while maintaining security logs at the IdP level.
Session management and security checks
SSO also governs session length. Tokens typically expire after a set time, forcing the user to re-authenticate. Conditional access policies may require new authentication if risk signals appear, such as a login attempt from an unfamiliar device or country. This reduces exposure if a token is stolen.
Business impact of SSO flow
SSO simplifies access for staff but also concentrates risk. If an attacker gains access to the IdP, they potentially gain access to everything. This is why most insurers and regulators now expect SSO to be paired with multi-factor authentication and tight monitoring.
Benefits of SSO for businesses
Single sign-on is often viewed as a convenience tool, but its true value lies in how it reduces security risks and improves efficiency. These are the main benefits for UK businesses.
- Fewer passwords, fewer phishing risks: With traditional logins, staff manage multiple usernames and passwords. This often leads to reuse, weak choices, or unsafe storage. Every extra password is another chance for attackers to phish or steal. By reducing the number of passwords employees need, SSO lowers the attack surface and makes phishing campaigns less effective.
- Enhanced employee experience: SSO eliminates the frustration of frequent logins. Staff sign in once and then move freely between applications without interruption. This saves time each day and reduces downtime caused by forgotten passwords or repeated resets. A smoother login process also encourages adoption of new business tools.
- Easier to enforce MFA and compliance: SSO centralises login, allowing security teams to enforce multi-factor authentication (MFA) at one point instead of across dozens of apps. This helps businesses meet compliance requirements under Cyber Essentials, ISO 27001, and FCA guidelines. Insurers also view SSO combined with MFA as evidence of strong risk management.
- Centralised identity management: Instead of managing accounts and permissions in every single app, IT teams control access through the identity provider. This makes it easier to grant or revoke rights, set policies consistently, and audit who accessed what and when. Centralisation also reduces errors that can leave accounts exposed.
- Faster onboarding and offboarding of staff: When new staff join, they can be granted access to all their tools in one step through SSO. When employees leave, disabling their SSO account immediately cuts off access everywhere. This speeds up HR processes and reduces the risk of ex-staff retaining access to sensitive systems.
Single sign-on vs multi-factor authentication (MFA)
Single sign-on (SSO) and multi-factor authentication (MFA) are often mentioned together, but they serve different purposes. One controls how many times you log in, the other controls how securely you log in. For businesses, understanding the difference and how they work together is critical to reducing account takeover risks and meeting insurance and compliance standards.
What they are and how they work together
SSO enables a user to log in once with a single set of credentials and then access multiple applications without re-entering their password. MFA adds an extra layer by requiring two or more forms of verification before access is granted, such as a password plus an authenticator app code.
The two are not alternatives. They complement each other. Together, they deliver both convenience and security. SSO reduces password fatigue while MFA protects against stolen or weak credentials.
Why SSO needs MFA to be secure
On its own, SSO can create a single point of failure. If a cybercriminal steals one SSO password, they may gain access to every connected system. Adding MFA to SSO prevents this scenario by forcing attackers to also bypass an additional factor, such as a hardware token or biometric check. For businesses, this combination reduces the risk of phishing, credential stuffing, and brute-force attacks.
Insurance and compliance implications
Insurers and regulators now expect both SSO and MFA on critical systems, particularly email, cloud platforms, and admin accounts. Cyber insurance policies often list MFA as a baseline requirement, and frameworks like Cyber Essentials and ISO 27001 include access management as a core control. Many insurers also recommend SSO as a way to centralise identity and make MFA enforcement easier.
Using SSO without MFA is seen as high risk. Using both is increasingly treated as the gold standard.
Read our MFA guide for more details on how MFA supports cyber insurance and compliance.
SSO vs traditional login
Traditional login means every application has its own username and password. Staff juggle multiple sets of credentials, which creates frustration and security risk. Single sign-on replaces this with one secure login that works across all authorised apps. The table below highlights the key differences and explains why many businesses now view SSO as the safer and more efficient choice.
How to configure single sign-on for your business
Most SSO platforms use a per-user, per-month model, with prices starting at just a few pounds. Costs vary depending on features such as MFA, conditional access, and reporting. Some platforms, like Microsoft 365 and Google Workspace, include basic SSO in their business plans. For UK firms, the real investment often comes from setup, integration, and staff training.
The table below shows starting prices and key features from leading providers.
Choose a provider
Start by selecting an SSO provider that aligns with your business's size, budget, and technical stack. Common options in the UK include Microsoft Azure Active Directory, Okta, OneLogin, and Ping Identity. If you already use Microsoft 365, Azure AD often integrates most easily. SaaS-heavy businesses may prefer Okta for its wide library of pre-built connectors. Evaluate providers on:
- Compatibility with your existing cloud apps and on-premise systems.
- Support for modern protocols like SAML 2.0 and OpenID Connect (OIDC).
- Built-in MFA support and conditional access policies.
- UK data centre presence or GDPR compliance features.
Integrate with your identity provider (IdP)
The IdP acts as the source of truth for your users. Connect your chosen SSO service to the identity provider so accounts, groups, and roles are synchronised. For most SMEs, this means linking your SSO provider with Microsoft Active Directory or Azure AD.
For SaaS-first companies, this might mean building out Okta or OneLogin as your central identity store.
Configure trust relationships and security settings
Each connected app must be configured to trust your SSO provider. This typically involves enabling SAML or OIDC, exchanging certificates, and setting up secure tokens. While doing this, enforce baseline security:
- Require MFA for all logins, particularly admin accounts.
- Apply conditional access rules (e.g. only allow logins from the UK or corporate devices).
- Set session timeouts and re-authentication policies.
- Ensure logs are sent to a central SIEM for monitoring.
Test and roll out to staff
Start with IT and admin users, then expand to a pilot group of staff. Testing ensures permissions, MFA prompts, and app access flows work as intended. Once tested, roll out business-wide with user training.
Provide clear guidance on how staff log in, how to use authenticator apps or tokens, and what to do if access fails.
Additional best practices to add value
To make this guide stand out, I’d also cover:
- Backup access accounts: Always retain at least two break-glass admin accounts outside of SSO in case the service fails.
- Shadow IT discovery: Audit which apps staff are actually using. Unauthorised apps may bypass SSO and create hidden risks.
- Vendor due diligence: Request details from your provider regarding uptime SLAs, data residency, and incident response procedures.
- Regular audits: Review SSO logs and access policies every quarter to ensure compliance. This is often requested during the underwriting process for cyber insurance.
How much does single sign-on cost?
The cost of single sign-on depends on your provider, the number of users, and the features you need. Most SSO services charge on a per-user, per-month basis, with entry-level tiers starting at around £1-£5 per user each month. These basic plans often cover core authentication and access to a set number of apps.
As you move into higher tiers, pricing typically rises to £6-£15 per user, per month. These plans usually include advanced features such as built-in multi-factor authentication, conditional access policies, security reporting, and integrations with a wider range of cloud applications.
Some platforms bundle SSO at no extra cost. For example, Google Workspace and Microsoft 365 include basic SSO functionality, although advanced configuration or cross-app integrations may still require third-party add-ons or premium licences.
Implementation also adds to the cost. Smaller businesses may be able to set up SSO in-house, but mid-sized and larger firms often bring in IT support or specialist consultants. Depending on complexity, implementation projects can range from a few hundred to several thousand pounds.
For most SMEs, the return on investment is clear. SSO reduces password resets, lowers phishing risks, and satisfies insurer and compliance requirements, often offsetting the upfront investment.
SSO provider pricing
SSO pricing depends on the provider, the features included, and the number of users that need to be supported. This snapshot highlights entry-level costs and what you actually get at each tier, so you can compare options without wading through marketing pages.
Common security risks of SSO
Single sign-on simplifies access, but it also concentrates risk. If attackers compromise an SSO login, they can move freely across every connected system. Understanding the risks helps businesses close gaps before they are exploited.
Stolen SSO credentials
One password often unlocks multiple applications. If a cybercriminal gains access through phishing or a data breach, they inherit wide privileges.
Prevention: Enforce multi-factor authentication, set strong password policies, and monitor for credential leaks.
No MFA in place
SSO without multi-factor authentication leaves accounts vulnerable. Attackers only need a single password to take control of multiple systems.
Prevention: Always pair SSO with MFA across email, cloud, and admin accounts.
Weak or misconfigured trust relationships
SSO relies on secure protocols like SAML or OIDC. If trust settings between your identity provider and apps are misconfigured, attackers may exploit the gap to bypass controls.
Prevention: Follow provider security guidance, use signed and encrypted tokens, and test configurations regularly.
Lack of access reviews and session controls
Over time, staff accounts accumulate unnecessary privileges. Without regular audits or session expiry, attackers who compromise an account may maintain access unnoticed.
Prevention: Schedule periodic access reviews, enforce least-privilege policies, and set session timeouts with automatic logouts.
Insufficient logging and monitoring
If activity logs are missing or ignored, suspicious sign-ins and token misuse may go undetected until too late.
Prevention: Enable audit logs across your identity provider and linked applications, and review alerts for unusual login patterns.
SSO and cyber insurance compliance
Cyber insurers are increasingly considering identity and access management when assessing risk. Single sign-on, when paired with multi-factor authentication, is considered a robust control that reduces the likelihood of credential theft and account takeover. Some insurers now make this combination a requirement before issuing cover, especially if your business handles sensitive customer data or relies heavily on cloud platforms.
Implementing SSO demonstrates that your business has mature access controls in place. It shows that accounts are centrally managed, login risks are reduced, and staff no longer rely on weak or reused passwords. For insurers, this signals lower exposure, which can result in broader coverage and lower premiums.
For more details on what insurers expect, see our guide on cyber insurance requirements.