What Is a Non-Human Identity (NHI)?

Non-Human Identity Explained

Non-human identities are the automated workforce of the modern technology stack. They power everything from CI/CD pipelines and microservices to serverless functions and automated data ingestion processes. Unlike human identities, which typically involve credentials such as usernames and passwords, NHIs use programmatic access. These include application secrets, JSON Web Tokens (JWTs), cloud identity and access management (IAM) roles, and secure shell (SSH) keys.

The sheer volume and diversity of non-human identities make them a complex security challenge. According to Wendi Whitmore, the Chief Security Intelligence Officer at Palo Alto Networks, the research shows.

“While attackers utilize AI to scale and accelerate threats across a hybrid workforce, where autonomous agents outnumber humans by 82:1, defenders must counter that speed with intelligent defense.”

Each NHI operates with a specific set of permissions and is often difficult to track, especially across multi-cloud and hybrid environments. Unmanaged NHIs can lead to unmonitored access, creating a massive security gap that attackers routinely target.

Categorizing Non-Human Identities

The NHI landscape can be broadly segmented into these major types. Securing each type requires a slightly different approach to credential management and access control.

• Workload Identities: Identities granted to applications, containers, or microservices, often using cloud-native IAM roles or service accounts. They typically require access to databases, storage, or other APIs. However, modern approaches leverage open standards like SPIFFE to issue cryptographic identities, replacing static credentials with short-lived, verifiable tokens.
• Machine Identities: Primarily certificates and keys used for device authentication, secure communication (TLS/SSL), and code signing. These are foundational for establishing trust between systems.
• Code-Based Secrets: Hard-coded credentials, API keys, tokens, or environment variables are often improperly embedded in application source code or configuration files.
• CI/CD Pipeline Accounts: Service accounts used by automation servers like Jenkins or GitHub Actions to deploy code into production environments, often possessing highly privileged access.
• Application Accounts: Dedicated service accounts created for specific applications to access the database, message queues, or external APIs. These accounts often accumulate standing privileges over time and are rarely audited after initial provisioning.

The Critical Distinction: Standing vs. Non-Standing Privileges

A fundamental security principle for non-human identities is the shift away from standing privileges. A standing privilege is permanent, constant access granted to an identity regardless of current need. This practice maximizes an account's risk exposure.

Non-standing privileges, conversely, are granted only when necessary and are revoked immediately upon completion of the required task. This concept is often referred to as Just-in-Time (JIT) access. Applying JIT to NHIs dramatically reduces the window of opportunity for attackers.

Table 1: Standing Privilege vs Non-Standing (JIT) Privilege

Why Standing Privileges Are Targeted

Attackers actively search for non-human identities with standing privileges. A static, permanent API key or service account provides an attacker with a stable and often unnoticed backdoor.

Unit 42 threat intelligence observes that once an attacker gains initial access, one of the first actions is to enumerate local systems for these stored credentials. The successful theft of a long-lived cloud access key allows for sustained malicious activity, often manifesting as resource manipulation or data exfiltration.

Lateral Movement and Attacker Workflow

Non-human identities are the invisible targets that enable an attacker’s transition from an initial foothold to a full-scale compromise of the environment. Attackers exploit the interdependencies among cloud workloads and microservices.

A single, low-privilege service account within a container may be able to assume a more privileged role in another service. This technique is a common form of privilege escalation and lateral movement.

Unit 42's analysis of cloud breaches shows that the typical attack lifecycle often hinges on exploiting misconfigured non-human identities.

Non-Human Identity Exploitation Tactics

1. Initial Compromise: An externally facing workload (e.g., a vulnerable web application) is compromised, often via a known vulnerability or a simple cloud misconfiguration.
2. Credential Theft: The attacker searches the compromised host's environment variables, configuration files, or local metadata for credentials associated with non-human entities (API keys, tokens, or IAM role assumption keys). This maps to MITRE ATT&CK techniques:
   1. T1552: Unsecured Credentials (including T1552.001: Credentials In Files, and T1552.005: Cloud Instance Metadata API)
   2. T1528: Steal Application Access Token.
3. Lateral Pivot: Using the stolen credentials, the attacker impersonates the NHI to access other resources, such as a staging database or a CI/CD tool. This movement is often unmonitored because the actions appear to be routine account activity.
4. Resource Hijack: The attacker uses the newfound access to deploy malware, modify infrastructure as code, or exfiltrate high-value data. The breach transitions from a single point of failure to a full network segmentation bypass.

Effective NHI security, tied to the principle of least privilege, disrupts this workflow. By ensuring that each NHI has only the exact permissions needed for its current function, the attacker's ability to pivot is severely limited.

Operational Challenges and Implementation Steps for NHI

Managing non-human identities presents distinct operational challenges that extend beyond traditional human-centric identity and access management (IAM) programs. Automation is essential for managing the sheer scale of NHIs, especially in elastic cloud security environments.

Operational Challenges in NHI Management

• Visibility and Inventory: Organizations lack a comprehensive, centralized inventory of all non-human identities across multi-cloud and hybrid infrastructures, resulting in orphaned or forgotten accounts with excessive privileges.
• Secrets Sprawl: Uncontrolled creation and storage of API keys and secrets in code repositories, local file systems, or collaboration tools, making rotation and auditing nearly impossible.
• Policy Granularity: Defining fine-grained, least-privilege policies for applications with highly dynamic access requirements is functionally challenging for security teams.
• Rotation and Lifecycle: The operational overhead of automatically rotating thousands of non-human credentials, without causing service outages, often results in static, long-lived secrets.

Implementation Steps for NHI Security

To successfully manage NHI, a systematic, automated approach focusing on vaulting and JIT access is required.

1. Discover and Inventory All NHIs: Use Cloud Infrastructure Entitlement Management (CIEM) and Secrets Management tools to automatically discover every application, service, and machine identity across all environments.
2. Vault All Secrets: Centralize all non-human credentials into a secure, purpose-built vault that supports automated rotation and access control. Never store secrets directly in code or configuration files.
3. Implement Just-in-Time Access: Convert long-lived credentials into short-lived, ephemeral tokens. The NHI should request a secret/token from the vault only when it needs to access a resource.
4. Define and Enforce Least Privilege: Audit current NHI permissions and remove all standing privileges that are not actively required. Continuously monitor access policies for privilege creep.
5. Audit and Monitor Continuously: Integrate NHI access logs into a SIEM or XDR platform to detect anomalous behavior, such as a service account accessing a resource outside its typical operating hours or geographic location.

Non-Human Identity and Zero Trust Alignment

Non-human identity is a foundational pillar of any successful zero trust identity architecture. The Zero Trust model requires that no identity, human or non-human, is trusted by default. Access must be verified for every resource request, regardless of whether the identity is inside or outside the defined network perimeter.

Figure 1: NHI and the Zero Trust Cycle

For NHI, Zero Trust dictates continuous verification of the workload's identity and context. This goes beyond checking a static API key.

• Verify Identity: Is the source container/machine/function what it claims to be? Use cryptographic verification and machine certificates.
• Verify Context: What is the specific context of the request? Is the access being requested from the expected IP address, at the expected time, and for the expected resource?
• Verify Policy: Does the request align with the defined, least-privilege policy for that particular non-human identity?

By integrating NHI security into the core identity security controls, organizations ensure that every automated interaction adheres to the ‘Never Trust, Always Verify’ mantra. This provides an essential security layer for applications, microservices, and serverless functions that form the modern distributed perimeter.

CIEM, IAM, and PAM Relationships in NHI Security

Securing non-human identities is a joint effort that involves specialized tools for Identity and Access Management (IAM), Privileged Access Management (PAM), and Cloud Infrastructure Entitlement Management (CIEM). These tools must work together to provide a complete view of the NHI lifecycle.

Table 2: IAM, PAM and CIEM work together to provide a complete view of the NHI lifecycle.

The relationship is hierarchical and cooperative. IAM provides the foundational identity. PAM handles the secrets and privileged credentials used by the identity. CIEM ensures that the entitlements granted to the identity (via IAM) are minimized and continuously enforced.

This layered approach is mandatory for achieving optimal identity security across complex cloud and hybrid environments. For instance, Cortex XSIAM utilizes data from all three domains to detect and shut down a live threat actor using a stolen NHI credential almost instantaneously.

Strategic Management and Testing of NHIs

As organizations scale, the complexity of managing non-human identities (NHIs) increases exponentially. To move beyond basic discovery, security teams must understand the specific forms these identities take, how to test their defenses through simulation, and how to manage their entire lifecycle from creation to decommissioning.

Real-World Examples of NHIs

Understanding what qualifies as an NHI is the first step toward securing them. Common examples include:

• Service Accounts: Accounts used by an operating system to run background services or by a web server to access a database.
• OAuth Tokens: Used by third-party integrations (e.g., a Slack bot accessing your Google Calendar).
• Build Agents: Identities within CI/CD tools (like GitLab Runners) that require permission to push code to production.
• Serverless Functions: AWS Lambda or Azure Functions that trigger automatically and need specific IAM roles to process data.
• RPA Bots: Robotic Process Automation tools that "mimic" human UI actions to automate data entry across legacy systems.

Breach Simulation Plan for NHIs

Standard penetration testing often focuses on human entry points. A Non-Human Identity Breach Simulation specifically tests the resilience of machine-to-machine security. An effective simulation plan includes:

1. Secret Discovery Phase: Simulating an attacker scanning GitHub repositories, Docker images, or Wiki pages for "leaked" API keys or hard-coded secrets.
2. The "Impersonation" Test: Attempting to use a captured low-privilege token from one environment (e.g., Development) to access a higher-tier environment (e.g., Production).
3. Lateral Movement Simulation: Mimicking a compromised container to see if it can "sniff" the metadata service of the cloud provider to steal temporary security credentials.
4. Blast Radius Assessment: Measuring how many resources are accessible once an NHI is compromised. If a single API key can delete an entire S3 bucket, the simulation has identified a critical failure in the Principle of Least Privilege.

NHI Identity Lifecycle Management (NHI-LM)

Unlike human employees, who have a "Joiner-Mover-Leaver" process tied to HR, NHIs are often created ad hoc by developers. A comprehensive Identity Lifecycle Management framework for NHIs includes:

• Onboarding & Registration: Every NHI must have an assigned "Owner" (a human or team) and a defined purpose documented in a centralized registry.
• Automated Provisioning: Use Infrastructure as Code (IaC) to ensure NHIs are created with specific, pre-approved permissions rather than manual, broad-access setups.
• Continuous Governance (The "Mover" Phase): As an application evolves, its NHI permissions often "creep." Periodic automated reviews must prune unused permissions or update credentials when the application architecture changes.
• Decommissioning (The "Leaver" Phase): This is the most common gap. When a project is retired or a microservice is deleted, the associated secrets and service accounts must be systematically revoked. "Orphaned" NHIs are among the highest risks in cloud environments.

Non-Human Identity FAQs