What is non-human identity (NHI)?

For the longest time, IT security was only centered around human identities, i.e., people who accessed systems through usernames, passwords, and multi-factor authentication. However, automation, cloud services, and machine-to-machine communication have become increasingly popular. As a result, a Non-Human Identity(NHI) that authenticates and authorizes interactions between these systems was introduced.

In this article, you'll learn about NHIs and their challenges. We'll also cover best practices for managing NHIs, with practical examples of how you can integrate these practices into your infrastructure. Finally, you'll have an outlook on how things might change in the future and how you can prepare for these changes.

What are NHIs?

A Non-Human Identity is a digital entity that requires authentication and authorization to gain access to specific resources or interact with IT infrastructure. Unlike human identities, NHIs exist mainly for machine-to-machine interactions.

You can think of them as digital passports for machines. Just as humans need usernames and passwords to access systems, machines need credentials to communicate securely with other applications. These credentials come in many forms, with popular examples including API keys, OAuth tokens, SSH keys, service accounts, and, recently, LLM-powered AI agents/operators.

Now, you might wonder, "Don’t humans create these credentials and use them to perform certain operations programmatically?" Yes, humans initiate their creation, but once generated, NHIs operate autonomously. They authenticate independently, follow a different security model, are fully automated, and, more importantly, are often used by other machines.

The table below also provides an overview of the differences between human and non-human identities.

Human vs NHIAs shown above, human identity verifies access using multi-factor authentication(MFA) and manual intervention.

In contrast, NHIs use static secrets such as API keys and tokens.
Their governance and oversight are also somewhat different. Human identities are typically managed through HR-based processes that follow clear onboarding and offboarding procedures. NHIs, on the other hand, are automatically provisioned via scripts, Infrastructure as Code (IaC), or cloud-based automation, mostly without direct human supervision.

Why managing NHIs is harder than you think

NHIs are great because they simplify machine-to-machine interactions. However, if not properly handled, they might cause security and infrastructure-related issues, with some listed below.

Operational complexity and visibility

Unlike human identities, which remain relatively stable and are tied to specific individuals, NHIs are often created on the fly through automated processes; this dynamic nature makes them difficult to track, as they may only exist for minutes or hours before being decommissioned. Furthermore, in large organizations, the number of NHIs grows over time, with each one requiring specific permissions. Without centralized monitoring and direct human oversight, it becomes challenging for security teams to maintain visibility into which NHIs are active, their permissions, and whether they are still needed.

Security risks

When NHIs are not properly managed, they create unique security challenges that cyber attackers can exploit. Most non-human entities have more access than necessary, which increases the risk of misuse, and if an attacker should obtain such privileged NHI credentials, they can escalate access, move between systems undetected, and access sensitive data; a notable example is the Microsoft Azure Key Breach.

In 2023, a Microsoft account(MSA) signing key, which was supposed to be securely stored, was accidentally exposed. A threat actor tracked as Storm-0558 obtained this key and used it to forge authentication tokens. Using these tokens, the attackers accessed Outlook email accounts belonging to U.S. government agencies and private organizations without triggering traditional security alerts.

This single event shows a couple of things about NHIs. For one, the stolen signing key had broad permissions, with which the attackers easily escalated privileges. Additionally, Microsoft’s signing keys were not frequently rotated, which allowed the attack to operate over an extended period.

Governance

Another challenge with non-human identity management is their governance, which revolves around ownership and inconsistent policies.

Since NHIs belong to applications rather than people, they usually lack clear ownership and accountability. Unlike human users, who are solely responsible for their usernames, passwords, or MFA channels, NHIs are typically shared across teams. Over time, this leads to orphaned identities that sometimes persist beyond their needs.

Additionally, medium-to-large-sized organizations often create NHIs with different policy levels, with some granting excessive permissions. Without a centralized policy, these minor inconsistencies can weaken security and even increase compliance issues in the future.

Best practices for managing and securing NHIs

To mitigate the risks and challenges in managing non-human identities, let’s explore some best practices to help you stay ahead.

Implement robust access controls

Implementing robust security measures for access control is the first line of defense in NHI security. The main objective here is to guarantee that each NHI only gets the minimal necessary permissions, nothing more. Two key ways to do this are role-based access control(RBAC) and the principle of least privilege(PoLP).

The principle of least privilege complements this further. It states that you should grant NHIs only the bare minimum permissions required to perform their tasks. Say you have an API key that fetches read-only data from a third-party service. Instead of giving it broad access to write or delete data, you restrict it to just reading, thereby preventing accidental or malicious changes.

Lifecycle management and automation

NHIs are not supposed to remain static. To avoid security issues, they must be rotated regularly, deactivated when no longer required, and tracked throughout their lifecycle. Some strategies you can use to automate their lifecycle management include:

1. Regular credential rotation – NHIs should never rely on long-lived credentials. Instead, implement automated key and secrets policies so that secrets are frequently refreshed to minimize the risk of credential leaks.
2. Automated decommissioning – When an NHI is no longer in use, it should be quickly revoked to avoid lingering access. This includes removing associated API keys, deactivating service accounts, and clearing any extra permissions it might have.
3. Versioning and expiry policies – You should also define strict expiration policies for NHIs and enforceVersion control for credentials; this way, you can ensure old keys are phased out automatically rather than lingering in code repositories or configuration files.

You can reduce the risk of credential leaks and ensure your NHIs are always up to date and decommissioned when necessary with proper lifecycle management.

Continuous monitoring and auditing

Even with strict access controls, NHIs must be actively monitored to detect strange events and potential threats and to prevent misuse. One way to achieve this is to log and audit all access events and authentication. For example, if an API key is used to access a system it was never meant to interact with, logs and proper auditing can help you identify the issue and take action before any damage occurs.

Implement zero-trust architectures

One final yet critical best practice is adopting a zero-trust principle for NHIs. Just like human users, NHIs should always require verification. Every request must be authenticated, authorized, and continuously verified so that even if the NHI is compromised, an attacker can’t move freely across systems.

To implement this, you should replace static credentials with Ephemeral, short-lived tokens that expire automatically. For example, instead of storing long-term API keys in configuration files, use a secrets manager to generate temporary access tokens that refresh dynamically. This limits the window of opportunity for attackers to misuse compromised credentials. Zero trust, if implemented properly, can adjust to meet specific needs and still ensure an ROI on your security strategy.

Innovative approaches and future outlook

The number of NHIs grows daily, taking even more powerful forms, such as AI agents. For this reason, it’s important to implement robust strategies to improve them without compromising security. Some of the tech that could help shape things around this area are the blockchain and AI.

Blockchain’s main feature is its decentralized and tamper-proof nature. This could be applied to traditional identity management to reduce the risks of unauthorized changes and credential leaks. That is, instead of relying on traditional databases, blockchain can be used to register and verify identities without exposing sensitive credentials, using techniques such as hashing and Zero-knowledge proofs(ZKPs).

AI and machine learning-powered security is another game-changer. Machine learning models could be used to analyze NHI behavior in real-time and detect anomalies that traditional rule-based systems might miss. For example, such a system can flag an NHI that starts making excessive API calls or accessing unauthorized resources, even if the activity doesn’t trigger predefined alerts. Automated threat response systems can then isolate or revoke access before an incident escalates.

Regulatory and compliance considerations

While the tech improves, regulatory and compliance requirements, such as the General Data Protection Regulation(GDPR) and System and Organization Controls 2(SOC 2), will undoubtedly continue to change, and it’s important to stay ahead.

The best way to prepare for these changes and ensure compliance is to implement the best practices we’ve covered in this article, which include enforcing strict access controls, implementing security policies, continuously monitoring and auditing your NHIs, and properly managing their lifecycle. In addition, you don’t have to reinvent the wheel to benefit from these features. Leverage trusted tools like Doppler to automate your security and access management workflows.

Wrapping up

Now’s a great time to assess your current NHI management strategy. Are your credentials secure, regularly rotated, and properly monitored? If not, explore Doppler’s advanced secret management solutions to help you reduce attack surfaces and improve overall security.

Ready to take control of your NHIs? Try out a free demo to experience how Doppler simplifies NHI management for reliable security.