Non-Human Identities (NHIs) are digital credentials assigned to automated systems, applications, bots, APIs, and service accounts. Unlike human identities, which are tied to individual users and protected by Multi-Factor Authentication (MFA), NHIs facilitate machine-to-machine (M2M) communication autonomously.

In modern cloud-first environments, NHIs often outnumber human users by as much as 45 to 1. Because they often possess elevated privileges to move data between systems—and frequently lack the behavioral monitoring applied to humans—they represent one of the fastest-growing attack surfaces for data exfiltration and lateral movement.

Types of Non-Human Identities

NHIs are not a monolith. They generally fall into four categories:

  1. Service Accounts: Used by applications to interact with the operating system or other applications.
  2. Secrets & API Keys: Credentials used by developers to allow one software service to 'talk' to another.
  3. Bots & RPA: Robotic Process Automation identities that perform repetitive human tasks.
  4. Workload Identities: Identities assigned to cloud resources like virtual machines, containers, or serverless functions.

NHI Challenges in Different Industries

  • Finance (Algorithmic Trading & GLBA): In finance, NHIs are used for high-frequency trading and automated financial reporting. If an API key for a financial database is compromised, an attacker can exfiltrate sensitive NPI at machine speed. Managing these secrets is essential for GLBA and PCI DSS compliance.
  • Healthcare (IoT & Patient Monitoring): Hospitals rely on NHIs for connected medical devices (IoT). A compromised identity on a patient monitoring system could allow an attacker to intercept PHI or disrupt critical care. NHI management is a vital, yet often overlooked, part of HIPAA security audits.
  • Defense (DevSecOps & CMMC 2.0): Defense contractors use NHIs extensively in their CI/CD pipelines to automate software deployments. Under CMMC 2.0, contractors must ensure that these "machine identities" are subject to the same strict access controls and audit logging as human users. An unmanaged service account with access to CUI is a major vulnerability that could lead to an audit failure.

FAQs: Non-Human Identities (NHIs)

What is the difference between an NHI and a Service Account?

A service account is a type of NHI. NHI is the broad category that includes everything from an API key to a workload identity in a Kubernetes cluster.

Can you use MFA for Non-Human Identities?

Traditional MFA (like a text code) doesn't work for machines. Instead, NHIs should use "Secret Management" tools, hardware-backed certificates, or short-lived tokens that rotate automatically to provide a similar level of security.

Why are NHIs targeted by Advanced Persistent Threats (APTs)?

APTs target NHIs because they are a path of least resistance. Since NHIs often have high-level permissions and rarely change passwords, they allow attackers to move laterally and maintain a long-term presence in a network without being detected.

Does CMMC 2.0 specifically mention NHIs?

While it doesn't always use the term "NHI," it requires the management of "system accounts" and "identifiers." Control IA.L2-3.5.1 requires you to identify system users and processes acting on behalf of users, which includes every NHI in your environment.

What is "Secret Rotation" in the context of NHIs?

Secret rotation is the practice of automatically changing the passwords or API keys used by NHIs on a frequent basis (e.g., every 30 days or even every hour). This minimizes the window of opportunity for an attacker if a credential is leaked.