SSO and MFA were designed for interactive human access, so they miss credentials that authenticate programmatically or exist outside the SSO boundary. That leaves service accounts, API keys, and other NHI credentials outside the main control plane. Organisations need separate controls for discovery, lifecycle management, and attribution if they want full visibility.
Why This Matters for Security Teams
SSO and MFA close a major gap for interactive users, but they do not govern every credential that a modern organisation relies on. Service accounts, API keys, certificates, automation tokens, and embedded secrets often live outside the SSO boundary, which means they evade the visibility, policy, and revocation workflows teams assume are already in place. That is why credential sprawl becomes an operational risk, not just an access hygiene issue. The OWASP Non-Human Identity Top 10 treats unmanaged NHI credentials as a distinct class of exposure, and NHIMG research on the Guide to the Secret Sprawl Challenge shows how quickly those secrets can accumulate across apps, pipelines, and cloud services.
The core mistake is assuming that a stronger login experience for humans automatically reduces the number of machine credentials in circulation. It does not. SSO authenticates users into a central identity plane, while MFA adds assurance at login time; neither discovers orphaned API keys, rotates long-lived tokens, or ties a secret back to the workload that uses it. In practice, many security teams encounter credential sprawl only after a leak, outage, or incident response exercise has already exposed how much of the environment sat outside SSO control.
How It Works in Practice
Credential sprawl persists because machine access is created for convenience and retained for reliability. A CI/CD job needs a token to deploy. A script needs a database password. An integration needs an API key. Over time, each of these becomes a durable credential with unclear ownership, inconsistent rotation, and weak attribution. SSO does not remove that problem because the credential is often not a human login at all.
Security teams reduce sprawl by treating non-human access as a separate lifecycle. That usually means discovering all secrets first, then classifying them by workload, privilege, and exposure path. The next step is to replace static credentials with short-lived alternatives where possible. Current guidance suggests using workload identity, just-in-time issuance, and automated revocation so access is bound to the task, not to an enduring secret. For humans, NIST SP 800-63 Digital Identity Guidelines remain relevant for authentication assurance, but they do not substitute for NHI governance.
- Inventory machine credentials across code, pipelines, cloud accounts, and SaaS integrations.
- Map each secret to an owner, workload, and expiry date.
- Prefer ephemeral tokens, workload identity, and brokered access over shared static secrets.
- Log issuance, use, and revocation so attribution does not depend on guesswork.
NHIMG research on Ultimate Guide to NHIs — Static vs Dynamic Secrets reinforces why TTL matters differently for machine access: the shorter the lifespan of a secret, the smaller the blast radius when it is exposed. These controls tend to break down when legacy systems require shared credentials or when automation is distributed across multiple cloud boundaries without a central secret inventory.
Common Variations and Edge Cases
Tighter credential control often increases operational overhead, requiring organisations to balance reduced exposure against deployment friction and system compatibility. That tradeoff is especially visible in older applications, third-party integrations, and long-running batch jobs where SSO cannot be inserted cleanly. Best practice is evolving here: there is no universal standard for every migration path, but the direction is clear. Static secrets should be phased down wherever runtime issuance or workload-bound identity is possible.
Some teams also overestimate what MFA can do for privileged service access. MFA is excellent for interactive human sessions, but it does not help when the credential is stored in a pipeline variable, copied into a config file, or injected into a container at build time. In those cases, the real control is secret governance, not login enforcement. NHIMG’s 2024 Non-Human Identity Security Report found that 88.5% of organisations say their non-human IAM practices lag behind or are only on par with human IAM, which is a strong signal that the control gap is organisational, not just technical.
For practitioners, the important distinction is simple: SSO and MFA reduce risk at the human access boundary, but credential sprawl lives in the machine layer, where discovery, lifecycle management, and attribution must be handled separately.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 address the attack and risk surface, while NIST SP 800-63 and NIST AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-01 | SSO gaps leave unmanaged non-human secrets outside central identity control. |
| NIST SP 800-63 | IAL2 | Shows where human identity assurance applies, but not to machine secrets. |
| NIST AI RMF | GOVERN | Autonomous and automated access needs accountable governance across the full lifecycle. |
Use NIST identity assurance for users, then add separate controls for non-human credential discovery and rotation.
