Build vs buy for authorization: why in-house auth is harder

At a glance

What this is: This is Cerbos’s build-vs-buy analysis for authorization, and its core finding is that most organisations should buy rather than build when access logic is complex, regulated, or expected to scale.

Why it matters: It matters because authorization sits at the center of IAM, NHI, and application control decisions, so weak design choices create security, compliance, and scalability failures across human and machine identities.

By the numbers:

• 70% of organisations grant AI systems more access than they would give a human employee performing the exact same job.

👉 Read Cerbos's guide to build vs buy authorization decisions

Context

Authorization is the decision layer that determines who or what can do what inside an application, and it becomes fragile when rules are hardcoded into product logic. For IAM teams, that fragility shows up as slower delivery, harder audits, and more risk every time roles, tenants, or policy requirements change.

The article argues that this problem is no longer just a software-engineering preference. When authorization affects compliance, scale, and user experience at the same time, the build-vs-buy decision becomes an identity governance question, not only an architecture choice.

Key questions

Q: When should teams build authorization logic instead of buying it?

A: Build only when authorization is tightly tied to product differentiation, the rules are simple enough to stay stable, and the team can maintain the code long term. If policy changes are frequent, compliance is demanding, or access complexity is likely to grow, buying is usually the safer and faster route.

Q: Why does custom authorization become risky as systems scale?

A: Custom authorization becomes risky because access rules tend to multiply faster than development teams can safely refactor them. That creates code-level policy drift, maintenance overhead, and higher chances of inconsistent enforcement across services, especially in regulated or multi-tenant environments.

Q: How do security teams judge whether an authorization platform is flexible enough?

A: Look for a policy model that can handle new roles, new attributes, new services, and new compliance constraints without a rebuild. The test is whether the system can evolve with the business while preserving auditability, performance, and clear ownership of enforcement.

Q: What is the biggest hidden cost of rolling your own authorization?

A: The biggest hidden cost is developer time, especially when access changes require code edits, testing, and redeployment. That cost is often larger and less predictable than purchase price, and it can slow product delivery while increasing the chance of mistakes in critical access logic.

Technical breakdown

Why hardcoded authorization breaks at scale

Hardcoded authorization embeds access decisions directly into application code, which makes policy changes expensive and error-prone. As role counts, tenant complexity, and compliance requirements grow, every permission change can require code edits, testing, and redeployment. That creates technical debt and increases the chance that a small policy mistake becomes a security issue. The deeper the coupling between business logic and access logic, the harder it is to keep authorization accurate without slowing product delivery.

Practical implication: move away from code-bound access logic when policy changes are frequent or business-critical.

Why flexibility matters more than perfect fit

A custom authorization layer often starts with a narrow use case, but access control rarely stays narrow for long. New attributes, new roles, new services, and new regulatory constraints force the system to evolve. That is why flexibility matters more than an exact one-time fit. A policy model that can accommodate change without a rebuild is more defensible than one that only works for today’s architecture. This is especially true in multi-tenant and regulated environments where access semantics change under pressure.

Practical implication: test whether the authorization approach can absorb new policy patterns without redesign.

Build vs buy in regulated environments

Regulated industries need visibility into how authorization is enforced, not just whether access is denied or allowed. That means teams must consider auditability, traceability, and operational ownership as part of the architecture decision. A buy decision can reduce implementation burden if the solution is transparent enough to satisfy compliance evidence requirements. A build decision can make sense when the organisation truly needs full control, but only if it can sustain ongoing maintenance and expertise.

Practical implication: evaluate auditability and ownership requirements before treating custom build as the safer option.

Threat narrative

Attacker objective: The objective is to exploit weak or inconsistent access decisions to reach protected data, actions, or administrative functions.

1. Entry occurs when access rules are embedded in application code and change slowly relative to the business, creating gaps between intended and enforced permissions.
2. Escalation happens when developers must patch or recompile to change policy, which encourages shortcuts, stale logic, and inconsistent role handling across services.
3. Impact follows when authorization errors create breaches, compliance failures, or latency so severe that the software becomes unusable.

Breaches seen in the wild

• IOS app secrets leakage report — iOS apps leaking hardcoded secrets and credentials endangering user privacy.
• ASP.NET machine keys RCE attack — 3,000+ exposed ASP.NET machine keys enabled remote code execution.

Read our 52 NHI Breaches Analysis report for a comprehensive view of breaches impacting Non-Human Identities including AI Agents.

NHI Mgmt Group analysis

Authorization design is now an identity governance decision, not a code preference. When access rules determine who can read, change, or delegate access, the control surface belongs in governance as much as in engineering. The article’s core point is that hidden authorization logic creates audit and change-management risk that IAM teams cannot ignore. Practitioners should treat authorization architecture as part of access governance, not a side effect of application design.

Hardcoded authorization creates policy drift because access intent changes faster than release cycles. The article shows that every role change, tenant change, or regulatory adjustment introduces pressure on code-based permissions. That is a classic control gap in modern application identity: enforcement becomes frozen while business context keeps moving. The practical conclusion is that static code paths are a poor fit where policy churn is normal.

Build for competitive advantage, buy for parity still applies, but authorization usually sits on the parity side. The article argues that very few organisations differentiate on their access engine itself, while many absorb avoidable delivery and maintenance cost by building it. That makes authorization a category where governance fit and operational durability matter more than architectural pride. Teams should challenge whether custom auth is truly a differentiator or just inherited complexity.

Regulated access control needs provable visibility more than bespoke cleverness. In finance, healthcare, insurance, and similar environments, the issue is not simply whether authorization works, but whether it can be explained, reviewed, and maintained over time. The strongest governance posture is one where policy enforcement stays legible under audit and resilient under growth. Practitioners should prioritise enforceability over novelty.

Access control debt behaves like any other hidden infrastructure debt: it slows everything else down. The article’s maintenance example shows that repeated permission edits in source code consume engineering time and pull attention away from core product work. That makes authorization debt a lifecycle issue, not just an implementation issue. Security leaders should account for it as ongoing operational drag, not a one-time build cost.

From our research:

• 88.5% of organisations acknowledge that their non-human IAM practices lag behind or are merely on par with their human identity and access management efforts, according to The 2024 Non-Human Identity Security Report.
• 59.8% of organisations see value in a solution that simplifies non-human access management and introduces dynamic ephemeral credentials, according to Aembit research.
• For a broader governance baseline, Ultimate Guide to NHIs , Standards helps teams map access controls to NHI security frameworks.

What this signals

Authorization is converging with NHI governance because policy complexity now spans human users, service accounts, and automated systems. When access rules live inside application code, identity teams lose the ability to reason about them as a shared control plane. That is exactly where modern programme design has to move, especially as AI-enabled systems inherit the same entitlement sprawl that workload identities already expose.

Access control debt is becoming a measurable drag on security operations. The question is no longer whether teams can implement policy, but whether they can maintain it without creating latency, audit gaps, or release bottlenecks. For practitioners, that means architecture decisions need to be evaluated against operating model capacity, not just feature fit.

At the governance layer, the signal is clear: teams that cannot explain access decisions quickly enough will struggle under both security review and compliance pressure. Aligning authorization with policy governance, lifecycle review, and audit evidence is becoming a prerequisite for scale, not an optimisation.

For practitioners

• Map authorization ownership to governance Assign clear ownership for access policy, enforcement, and audit evidence before deciding whether to build or buy. Treat the authorization layer as part of identity governance, not just application code.
• Test for policy churn tolerance Evaluate how often roles, attributes, and compliance rules change in your environment, then check whether the chosen approach can absorb that churn without repeated code changes or redeployments.
• Run a maintenance cost model Compare developer time, testing effort, release delays, and future scaling overhead against the visible purchase price so hidden build costs do not stay off the ledger.
• Validate audit visibility early Confirm that the access model produces enough traceability for security and compliance teams to explain decisions during reviews, investigations, and regulatory checks.

Key takeaways

• Authorization belongs in governance discussions because hidden access logic can create security, compliance, and release risk at the same time.
• Custom authorization gets more fragile as roles, tenants, and regulations multiply, which is why flexibility and auditability matter more than a perfect initial fit.
• For most organisations, the decision is less about technical pride and more about whether the team can sustain the maintenance burden without slowing the product.

Key terms

• Authorization layer: The authorization layer is the part of a system that decides whether a user, service, or automated actor can perform a specific action. In modern applications, it should be governed as a policy control rather than buried in code so it can be reviewed, changed, and audited independently.
• Policy drift: Policy drift happens when the way access is enforced no longer matches the way the business or security team intended it to work. In authorization systems, this usually appears when code changes, role changes, or regulatory updates outpace the control model that was originally built.
• Access control debt: Access control debt is the accumulated operational cost of decisions that made authorization easy to ship but hard to maintain later. It shows up as repeated code edits, testing overhead, slower releases, and higher risk when permissions or business rules need to change.

Deepen your knowledge

NHI governance, agentic AI identity, and machine identity security are core topics in our NHI Foundation Level course, the industry's only accredited NHI security programme. If you are responsible for identity security strategy or NHI governance in your organisation, it is worth exploring.

This post draws on content published by Cerbos: a guide to build vs buy for authorization. Read the original.