Non-Human Identity Security: The Hidden Risk in Zero Trust Architecture

In the race to secure human users through multi-factor authentication, privileged access management, and behavioral analytics, enterprises have overlooked a growing threat hiding in plain sight. Non-human identities (NHI) now outnumber human users by 45:1, yet they remain largely untracked, unmanaged, and unprotected.

These service accounts, API keys, machine identities, and automated systems represent the invisible majority of your enterprise environment. Recent research by the Cloud Security Alliance found that only 15% of organizations feel highly confident in preventing NHI attacks, while 69% express concerns about them. And they're becoming your weakest link in what should be your strongest security posture.

The proliferation problem: How we got here

The shift to microservices architecture and cloud-native applications has created an explosion of non-human identities. Every system that needs to communicate with another system requires credentials. Every automated process needs an identity. Every API integration demands authentication.

But here's the critical issue: while we've built sophisticated processes around human identity lifecycle management, non-human identities are created through ad hoc processes and forgotten just as quickly. It's as if every employee who ever worked at your company remained active in your HR system, even decades after leaving.

This happens because most roles focus on value creation through addition, not subtraction. Cleaning up technical debt, including orphaned identities, rarely gets the spotlight. Even worse, when the developer who created a service account leaves the company, the next product owner inherits a mystery identity they're too afraid to decommission, just in case it's system critical.

The problem is only accelerating. As we move toward agentic artificial intelligence (AI) systems that need to interact with countless services and APIs, the proliferation of non-human identities will explode exponentially.

The zero trust paradox

Zero trust architecture promises to verify every entity continuously and grant only the minimum necessary privileges. The National Institute of Standards and Technology (NIST) has acknowledged this challenge, noting in their zero trust architecture guidance that securing non-human identities remains an "open issue" that requires equal treatment with human users for authentication, authorization, and access control.

Here's how NHIs systematically undermine zero trust principles in four critical ways:

Developers often over-privilege service accounts to "make it work" rather than taking time to understand granular permission requirements. Focused on functionality over security, they grant admin or domain-level access because it's faster than debugging permission failures.

Credentials frequently get hardcoded directly in configuration files or application code, especially in on-premises systems. These embedded secrets create persistent, unrotated attack vectors that bypass sophisticated access controls entirely.

Service accounts remain active long after their associated services are decommissioned, creating dormant but highly privileged entry points. These zombie credentials persist because decommissioning processes often lag behind rapid development cycles.

When original creators leave and documentation is poor, entire teams become paralyzed by uncertainty. They're afraid to touch identities whose purpose they don't understand, leaving over-privileged accounts indefinitely active.

The discovery challenge

Even security-conscious organizations struggle to maintain accurate inventories of their non-human identities. The barriers are both technical and organizational.

While great companies rely on great processes for human onboarding, non-human identity creation often happens through informal channels. This leads to arbitrary naming conventions, unclear ownership, and minimal metadata that makes future management nearly impossible.

Unlike human identities that naturally centralize through HR systems, non-human identities are created across cloud platforms, on-premises systems, code repositories, and third-party services. Even when organizations mandate central credential management, there's often no enforcement mechanism to ensure compliance.

Credentials often get stored in configuration management systems, container images, CI/CD pipelines, and application code, creating a sprawling attack surface that's nearly impossible to inventory through traditional means. Research shows that 23.77 million new secrets were leaked on GitHub in 2024 alone, representing a 25% increase from the previous year.

As business units adopt SaaS tools and cloud services independently, they create service accounts and API integrations that bypass central IT oversight entirely. This shadow IT multiplication creates blind spots that traditional discovery tools cannot penetrate.

A framework for risk-based remediation

Given the scale of most non-human identity sprawl, organizations need a systematic approach to prioritize their remediation efforts. Focus on these key dimensions:

Privilege level: Domain administrators and accounts with write access to critical systems pose exponentially higher risk than read-only credentials.

Access scope: Cross-environment access or internet-facing credentials should be addressed before isolated, internal-only accounts.

Credential age: Older, never-rotated credentials represent higher compromise risk, especially those created years ago with weaker standards.

Usage patterns: Dormant accounts with high privileges are critical red flags. Active accounts with unusual access patterns may indicate compromise.

Ownership clarity: Any identity marked as "owner unknown" or assigned to departed employees should be considered high risk until proven otherwise.

Business criticality: Systems supporting revenue generation, regulatory compliance, or safety require immediate attention regardless of other risk factors.

Use these dimensions to create a standardized remediation backlog that aligns with your organization's risk tolerance and compliance requirements.

Building sustainable governance

Preventing non-human identity sprawl requires both technology and cultural change.

Organizations should deploy continuous scanning across cloud environments, on-premises systems, code repositories, and secrets management platforms. AI-powered tools are increasingly capable of identifying credentials in unexpected places and mapping their usage patterns.

Implementing privileged access management solutions that can store, rotate, and monitor all non-human credentials provides essential centralization. However, technology alone won't solve the problem if teams can still create credentials outside these systems.

Remove the friction from doing the right thing by implementing self-service identity creation workflows. These should enforce naming standards, proper documentation, and appropriate privilege scoping by default, making compliance easier than shortcuts.

Organizations should implement policies that automatically disable unused identities after defined inactivity thresholds. Make decommissioning the default action rather than a manual decision that requires someone to take ownership of potential risk.

Delivering governance at scale may be the hardest challenge of all. Unless your staff work directly in identity and access management, they likely give minimal thought to non-human identities. Organizations must begin treating these identities as first-class security assets worthy of the same attention given to human users.

The path forward

Non-human identities represent one of the largest gaps between security theory and practice in modern enterprises. While we've invested heavily in securing human access, we've inadvertently created a parallel identity universe that operates with minimal oversight and maximum risk.

The organizations that address this challenge proactively will gain significant competitive advantages: reduced security risk, improved compliance posture, and greater operational efficiency. Those that ignore it will find their zero trust initiatives undermined by the very automation and integration that drives business value.