# Cis Docker 7.3

> Ensure that all Docker swarm overlay networks are encrypted

- Skill: `cyberstrikeus/cis-docker-7-3` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-docker-7-3`
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- Category: DevOps & Infra
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-docker-7-3

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# 7.3 Ensure that all Docker swarm overlay networks are encrypted (Manual)

## Profile Applicability

- Level 1 - Docker Swarm

## Description

Ensure that all Docker swarm overlay networks are encrypted.

## Rationale

By default, data exchanged between containers on nodes on the overlay network is not encrypted. This could potentially expose traffic between containers.

## Impact

None

## Audit Procedure

You should run the command below to ensure that each overlay network has been encrypted.

```
docker network ls --filter driver=overlay --quiet | xargs docker network inspect --format '{{.Name}} {{ .Options }}'
```

## Remediation

You should create overlay networks the with `--opt encrypted` flag.

## Default Value

By default, data exchanged in overlay networks in Docker swarm mode is not encrypted.

## References

1. https://docs.docker.com/network/overlay/#encrypt-traffic-on-an-overlay-network

## CIS Controls

| Controls Version | Control                                                                                                                                                                           | IG 1 | IG 2 | IG 3 |
| ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---- | ---- | ---- |
| v8               | 3.10 Encrypt Sensitive Data in Transit<br>Encrypt sensitive data in transit. Example implementations can include: Transport Layer Security (TLS) and Open Secure Shell (OpenSSH). |      | ●    | ●    |
| v7               | 14.4 Encrypt All Sensitive Information in Transit<br>Encrypt all sensitive information in transit.                                                                                |      | ●    | ●    |