Zero Trust Secrets Management: A Practical Guide

Zero trust security is more than a buzzword — it’s a fundamental shift in how we approach infrastructure security. The core premise is simple: no entity inside or outside your network should be automatically trusted. Every access request must be verified, every credential must be scoped, and every interaction must be logged.

In this guide, we’ll explore how to apply zero trust principles specifically to secrets management — one of the most critical and often overlooked aspects of a zero trust architecture.

Most organizations that adopt zero trust focus on network segmentation, identity verification, and endpoint security. But secrets — API keys, database credentials, TLS certificates, encryption keys — often remain managed through legacy practices: static files, environment variables, or shared credential stores with broad access.

A single leaked database password can undermine an otherwise robust zero trust deployment. If that password is long-lived and shared across multiple services, the blast radius of a compromise extends far beyond the initial breach point.

The numbers bear this out. According to recent industry reports, over 80% of data breaches involve compromised credentials. Many of these breaches go undetected for weeks or months because the compromised credentials appear legitimate — they are legitimate, just in the wrong hands.

Core Principles

Applying zero trust to secrets management means adopting four key principles:

1. Never Trust, Always Verify

Every access request must be authenticated and authorized, regardless of where it originates. A service running inside your Kubernetes cluster shouldn’t get database credentials just because it’s “internal.” It should prove its identity, demonstrate it has a legitimate need for those credentials, and receive only the specific secrets it requires.

With Mimir, this means every secret request goes through the authentication pipeline. Services authenticate using their platform identity — whether that’s a Kubernetes service account, an AWS IAM role, or an mTLS certificate — and Mimir verifies that identity against your configured access policies before releasing any secrets.

# Authenticate using AWS IAM identity
mimir auth enable aws
mimir auth login --method aws --role webapp-prod

# Read a secret — identity is verified on every request
mimir secret read database/creds/orders-api

2. Least Privilege Access

Grant only the minimum permissions needed for the task at hand. If a service needs read access to a specific database table, it shouldn’t receive admin credentials for the entire database server.

Mimir’s policy engine lets you define fine-grained access rules. You can scope secrets by service identity, environment (dev/staging/prod), time window, and even IP range. Policies are versioned and auditable, so you always know who has access to what and when that access was granted.

# Policy: orders-api can only read its own database credentials
policy "orders-api" {
  path "database/creds/orders-api" {
    capabilities = ["read"]
  }

  # Deny access to everything else
  path "database/creds/*" {
    capabilities = ["deny"]
  }
}

# Apply the policy
mimir policy write orders-api ./policies/orders-api.hcl

# Verify what a service can access
mimir policy test --identity orders-api --path "database/creds/orders-api" --action read
# ✓ Allowed

mimir policy test --identity orders-api --path "database/creds/users-api" --action read
# ✗ Denied

3. Assume Breach

Design systems assuming attackers have already gained internal access. This means limiting the blast radius of any single compromised credential and ensuring you can detect and respond to anomalous access patterns.

Dynamic secrets are the most effective tool here. Instead of a shared database password that could be exfiltrated and used indefinitely, Mimir generates unique, short-lived credentials for each access request. If one set of credentials is compromised, only that single session is affected — and the credentials expire automatically within minutes.

4. Continuous Verification

Trust shouldn’t be a one-time decision. Continuously validate that entities still deserve the access they’ve been granted. Monitor for anomalies, rotate credentials regularly, and re-authenticate when conditions change.

Mimir’s audit system tracks every secret access event and can trigger alerts when unusual patterns are detected — like a service requesting secrets it hasn’t accessed before, or a spike in credential requests from a single source.

Implementing with Mimir

Dynamic Secrets

Mimir’s dynamic secrets feature is designed with zero trust in mind. Instead of storing long-lived credentials, Mimir generates short-lived tokens on demand. Here’s how the flow works:

A service authenticates to Mimir using its platform identity
Mimir verifies the identity against your access policies
Mimir generates a unique, short-lived credential for the requested resource
The service uses the credential for its operation
The credential expires automatically after the configured TTL

Currently, Mimir supports dynamic secrets for PostgreSQL, MySQL, MongoDB, AWS IAM, GCP service accounts, and Azure AD. Each integration handles the full lifecycle — creation, rotation, and revocation — without any application changes required.

# Configure dynamic secrets for PostgreSQL
mimir secrets engine enable database
mimir secrets config write database/config/orders-db \
  --plugin postgresql \
  --connection-url "postgresql://{{username}}:{{password}}@db.internal:5432/orders" \
  --allowed-roles "orders-api" \
  --root-rotation-ttl 24h

# Define a role with scoped permissions
mimir secrets role write database/roles/orders-api \
  --db-name orders-db \
  --creation-statements "CREATE ROLE \"{{name}}\" WITH LOGIN PASSWORD '{{password}}' VALID UNTIL '{{expiration}}'; GRANT SELECT, INSERT ON orders TO \"{{name}}\";" \
  --default-ttl 1h \
  --max-ttl 4h

# Request dynamic credentials (returns unique, short-lived creds)
mimir secret read database/creds/orders-api

{
  "lease_id": "database/creds/orders-api/8f2k9x",
  "lease_duration": "1h",
  "data": {
    "username": "v-orders-api-8f2k9x",
    "password": "A1b-Xr9v2mKpQ..."
  }
}

Secret Versioning and Rotation

For secrets that can’t be made fully dynamic (such as encryption keys or third-party API tokens), Mimir provides automatic rotation with versioning. You define a rotation schedule and Mimir handles the rest — generating new credentials, distributing them to authorized services, and gracefully deprecating old versions.

The rotation process is zero-downtime by design. Mimir maintains a configurable overlap period where both old and new credentials are valid, giving services time to pick up the new version without interruption.

Transit Encryption

Mimir’s transit engine provides encryption-as-a-service, allowing applications to encrypt and decrypt data without ever handling encryption keys directly. The keys never leave Mimir’s boundary — applications send plaintext in and get ciphertext back (or vice versa).

This is particularly valuable for meeting compliance requirements around data encryption. Your application code never touches the keys, and Mimir handles key rotation automatically.

# Create a named encryption key
mimir transit key create customer-data --type aes256-gcm96

# Encrypt sensitive data (plaintext must be base64-encoded)
echo -n "ssn=123-45-6789" | base64 | \
  mimir transit encrypt customer-data --input -

# Output: mimir:v1:xK8s2pQ7...

# Decrypt when needed
mimir transit decrypt customer-data --ciphertext "mimir:v1:xK8s2pQ7..."
# ssn=123-45-6789

# Rotate the key — existing ciphertext still decryptable
mimir transit key rotate customer-data

Getting Started

Migrating to a zero trust secrets model doesn’t have to be a big-bang effort. We recommend a phased approach:

Phase 1: Visibility. Start by auditing your current secrets landscape. Identify where secrets are stored, how they’re distributed, and who has access. Mimir’s import tool can scan your existing credential stores and environment variables to build a complete inventory.

# Scan your environment for secrets
mimir scan --source env --source k8s-secrets --source dotenv \
  --output inventory.json

# Review the inventory
mimir scan report inventory.json
# Found 247 secrets across 3 sources:
#   - 89 environment variables (12 namespaces)
#   - 143 Kubernetes secrets (8 namespaces)
#   - 15 .env files (3 repositories)
#   - 23 HIGH RISK: long-lived, shared across services

Phase 2: Centralize. Move secrets into Mimir and update your services to fetch credentials from Mimir instead of local config files or environment variables. At this stage, you can use static secrets in Mimir — the goal is to centralize management and gain audit visibility.

Phase 3: Scope. Apply least-privilege policies to your centralized secrets. Review access patterns from your Phase 2 audit logs and tighten policies so each service only has access to the secrets it actually uses.

Phase 4: Dynamize. Migrate high-risk secrets to dynamic credentials. Start with database credentials, which typically offer the highest security ROI, then expand to cloud provider credentials and other integrations.

Phase 5: Monitor. Enable anomaly detection and integrate Mimir’s audit logs with your SIEM. Set up alerts for unusual access patterns and conduct regular access reviews.

Each phase builds on the previous one, and you get security improvements at every step — not just at the end.

Conclusion

Zero trust secrets management isn’t about deploying a single tool — it’s about shifting your security posture from “trust by default” to “verify everything.” Mimir provides the technical foundation, but the real transformation comes from applying these principles consistently across your organization.

The cost of getting secrets management wrong continues to rise. The good news is that the tools and practices for getting it right have never been more accessible. Start with visibility, apply least privilege, assume breach, and iterate from there.

Why Secrets Are a Zero Trust Blind Spot