When security teams talk about identity risk, they're usually thinking about people — phishing attacks, compromised passwords, account takeovers. But in 2026, the most dangerous identities in your Microsoft 365 environment aren't human at all.
Non-human identities (Non-Human Identities) are the service accounts, OAuth applications, AI agents, automation scripts, and API integrations that operate continuously in the background of your organisation's digital infrastructure. They authenticate to systems, access data, and perform actions — often with permissions that would make a senior administrator uncomfortable — and they do all of this without any of the controls that apply to human users.
No multi-factor authentication. No conditional access policies triggered by suspicious login locations. No one asking "should this account really have access to that?" Non-Human Identities are largely invisible, largely ungoverned, and increasingly, the entry point of choice for attackers.
The scale of the problem
In most enterprise Microsoft 365 environments, non-human identities outnumber human users by somewhere between 25 and 100 to 1. A mid-sized organisation with 500 employees might have 15,000 to 50,000 active service principals, OAuth consent grants, and registered applications — the vast majority of which were created without any formal security review and have never been audited since.
The numbers get more alarming when you look at what those identities can actually do. CyberArk's 2025 Identity Security Threat Landscape Report found that over 50 million machine identity credentials were found on the dark web — API keys, service account tokens, OAuth client secrets — a 250% increase since 2021. These aren't theoretical risks. They're active credentials being actively traded and used.
What makes Non-Human Identities different from human identities
Traditional identity security tools were designed for human users. They look for suspicious login patterns, unusual access times, unfamiliar locations — signals that make sense when you're watching for a compromised human account. Non-human identities break every one of these assumptions.
An Non-Human Identity that suddenly starts accessing 10,000 mailboxes at 3am isn't suspicious by traditional metrics — it might just be running a scheduled report. An API integration that silently accumulates permissions over six months doesn't trigger an alert. A service principal that was created by an employee who left the company three years ago and has been running quietly ever since — nobody's looking at that.
Non-Human Identities also lack the lifecycle controls that apply to human accounts. When an employee leaves, IT offboards their account. When an OAuth application is granted permissions by an admin who later leaves, those permissions stay — indefinitely. The application keeps running. The access keeps working. Nobody notices.
The three categories of Non-Human Identity risk
1. Excessive permissions
Most Non-Human Identities accumulate permissions over time. An integration that started with Mail.Read gets upgraded to Mail.ReadWrite when someone needs to send automated emails. Then Application.ReadWrite.All gets added when a new feature needs to register apps. Each change feels small and justified in context. The cumulative result is a service principal with near-administrator-level access that nobody has reviewed in three years.
2. Orphaned identities
When the human responsible for an Non-Human Identity leaves the organisation — or when the project the Non-Human Identity was created for ends — the identity typically stays. It continues to authenticate, continues to hold permissions, and continues to represent an attack surface. In our experience monitoring Microsoft 365 environments, unowned service principals typically represent 20-40% of all Non-Human Identities in a given tenant.
3. Credential age
Unlike human passwords, which most organisations rotate on a policy cycle, Non-Human Identity credentials — client secrets, API keys, certificates — are often set and forgotten. We regularly see credentials in Microsoft 365 tenants that were created two, three, or even five years ago and have never been rotated. An attacker who obtains one of these credentials has persistent, long-term access.
What you can do about it
The first step is visibility. You cannot govern what you cannot see. Most organisations start by being surprised at the sheer number of Non-Human Identities in their environment — typically many more than anyone expected. A thorough inventory of every service principal, OAuth application, and registered app in your Microsoft 365 tenant is the foundation of any Non-Human Identity security programme.
From there, the priorities are clear: identify unowned identities and assign accountability, review permissions against the principle of least privilege, establish credential rotation policies, and implement continuous monitoring to catch changes as they happen rather than during an annual audit.
The organisations that establish these foundations now — before an incident forces the issue — will be the resilience leaders of tomorrow. Those that don't will find out about their Non-Human Identity exposure in the worst possible way.
How AIRM helps
AIRM automatically discovers and inventories every non-human identity in your Microsoft 365 tenant — service principals, OAuth apps, AI agents, and automation accounts. Every identity is scored for risk, checked for ownership, and monitored continuously for changes. No agents required, no complex setup — connect in minutes.