# Security review of an agent sandbox provider

A deep review for teams that buy sandboxes for untrusted, multi-tenant agent code: isolation depth, tenancy, egress, secrets, snapshots, limits, logs and incident response.

- Level: Specialist
- Length: 75 minutes
- Exam questions: 11, pass mark 80%, up to 3 attempts
- Certificate: valid for 12 months

## What you will learn

- Explain defence in depth for isolation: a VM or application kernel boundary, with seccomp, namespaces and cgroups around it.
- Set tenancy rules: one sandbox for each customer, and hosts grouped by sensitivity.
- Design an egress policy that blocks private, loopback, link-local and metadata addresses after DNS resolution.
- Keep credentials out of the sandbox with short-lived scoped tokens or a proxy outside the boundary.
- Treat snapshots and persistent disks as data with an owner, a retention period and a deletion step.
- Define limits that fail closed, a log the code cannot edit, and an incident procedure.

## Lessons

1. [Isolation depth and tenancy](https://agentsandboxes.fyi/academy/review-agent-sandbox-security/isolation-depth-and-tenancy.md) (18 minutes)
2. [Egress, secrets and the metadata address](https://agentsandboxes.fyi/academy/review-agent-sandbox-security/egress-secrets-and-metadata.md) (18 minutes)
3. [State, snapshots and the data lifecycle](https://agentsandboxes.fyi/academy/review-agent-sandbox-security/state-snapshots-and-data-lifecycle.md) (15 minutes)
4. [Limits, logs and incident response](https://agentsandboxes.fyi/academy/review-agent-sandbox-security/limits-logs-and-incident-response.md) (18 minutes)

## Questions

### Does this course give me a security credential?

No. It gives a certificate of completion from this site. It does not vouch for you or for any provider, and it replaces neither a security audit nor legal advice.

### Does a microVM make a sandbox safe?

No. A microVM is a strong boundary, but data can still leave through the network, a secret in the environment or a snapshot. Review each path and test it.

### Do I need the Practitioner course first?

It helps. This course expects that you can write a threat model, score a shortlist and run the five escape checks from the Practitioner course.

Also on the [web page](https://agentsandboxes.fyi/academy/review-agent-sandbox-security).