Unauthorized Vault Access: The Biggest Security Gap Most Organizations Overlook

Secret managers and Vaults have become a cornerstone of modern secrets management. From cloud-native applications to hybrid and on-prem environments, organizations rely on Vault to control access to credentials, tokens, and sensitive configuration at scale.

Yet in recent conversations with security and identity teams, we’re seeing a consistent pattern: Vault is doing its job, and it's great! But, attackers are still getting in.

Not by breaking Vault itself, but by exploiting how Vault is deployed, accessed, and integrated into increasingly complex identity ecosystems.

This post looks at why unauthorized access to HashiCorp Vault is so difficult to detect, and why traditional approaches to Vault security are no longer enough.

The shift: AI Agents, DevOps & Workloads at Scale

A decade back as HashiCorp Vault released, the access patterns were relatively straightforward. Enterprises pushing the boundaries with their DevOps programs were adopting Vault. A small set of admins or developers were managing Vault, and applications authenticated in predictable ways.

That’s no longer the case. DevOps infrastructure and workloads have drastically scaled, AI Agents are scaling and generating even much more NHIs, to the point where we see Vault Secrets & NHIs driving workloads outnumber human employees 45:1, and growing. 

Secrets Managers and Vaults are accessed by:

• Assumed cloud roles spanning multiple accounts

• Kubernetes workloads and ephemeral pods

• CI/CD systems and automation

• Non-human identities (NHIs) and increasingly, AI agents

• Humans operating through machine-assumed privileges

  
  

From Vault’s point of view, much of this access looks valid. From a security point of view, that’s exactly the problem.

Unauthorized access rarely looks like a break-in anymore. It looks like legitimate identity activity.

Authentication bypass: when “legitimate” Vault access isn’t legitimate

Even centrally managed Vault deployments are not immune. Unauthorized access often occurs through weaknesses in authentication and identity configuration, including:

• Shadow admins using local Vault accounts not governed by the IdP

• Legacy auth methods are left enabled

• Lack of MFA enforcement

• Misconfigurations in Vault’s AWS or Kubernetes auth methods

• Unexpected use of NHIs or AI agents

• Role access by unauthorized user/NHI that used an assumed role 

  
  

In these cases, attackers don’t need to bypass Vault policies. They authenticate as something Vault already trusts.

To Vault, the access looks valid.To security teams, the risk is largely invisible.

Why unauthorized Vault access persists

The root cause isn’t a lack of tools. It’s fragmentation.

• Identity telemetry lives in IAM systems

• Vault authentication and audit logs live in Vault

• Application behavior lives elsewhere

• Machine identities and shadow access often go untracked

  
  

Without connecting these signals, organizations can’t trace the full chain:

Identity → Role Assumption → Vault Authentication → Secret Retrieval → Secret Usage

Attackers exploit this gap. If they can assume a role, impersonate a workload, or abuse a misconfiguration, they can access Vault and operate undetected.

Moving from Vault access control to Vault observability

Securing HashiCorp Vault today requires more than strong policies and access controls. It requires observability that turns Vault activity into actionable intelligence.

That means being able to:

• Detect unmanaged and shadow Vault instances

• Identify abnormal authentication paths and identity misuse

• Monitor secret retrieval behavior for anomalies

• Correlate identities, roles, Vault access, and downstream behavior

  
  

This is the difference between knowing that access happened and knowing whether that access introduced risk.

Final thoughts

Vaults and secrets managers remain foundational to secrets management. But as environments become more dynamic and identity-driven, unauthorized access increasingly hides inside what looks legitimate.

The organizations that succeed will be those that move beyond isolated Vault controls and toward continuous, identity-aware observability across Vault access and secret usage.

Because in modern environments, the question isn’t just who accessed Vault, it’s what they did with what they got.