Awesome
<!-- markdownlint-disable -->bastion
<!-- markdownlint-restore --> <!-- ** DO NOT EDIT THIS FILE ** ** This file was automatically generated by the `build-harness`. ** 1) Make all changes to `README.yaml` ** 2) Run `make init` (you only need to do this once) ** 3) Run`make readme` to rebuild this file. ** ** (We maintain HUNDREDS of open source projects. This is how we maintain our sanity.) ** -->This is a secure/locked-down bastion implemented as a Docker Container. It uses Alpine Linux as the base image and ships with support for Google Authenticator & DUO MFA support.
It was designed to be used on Kubernetes together with GitHub Authorized Keys to provide secure remote access to production clusters.
MFA Setup & Usage
Here's a demo of what a user experiences when setting up Google Authenticator for the first time.
When using Duo as the MFA provider, this becomes even more magical because Duo supports automatic Push notifications to your mobile device. Just approve the request on your mobile phone (e.g. with a thumb press on iOS) when prompted.
Slack Notifications
Here's what it looks like when someone connects to the bastion if Slack notifications are enabled.
We recommend using Slack notifications for self-reporting.
- Any time a user accesses production systems, they should reply to the slack notification to justify their remote access.
- A "buddy" should approve the login by adding a reaction (e.g. ✅).
- If no one approves the login, it should trigger an incident response to track down the unauthorized access.
This project is part of our comprehensive "SweetOps" approach towards DevOps. <img align="right" title="Share via Email" src="https://docs.cloudposse.com/images/ionicons/ios-email-outline-2.0.1-16x16-999999.svg"/> <img align="right" title="Share on Google+" src="https://docs.cloudposse.com/images/ionicons/social-googleplus-outline-2.0.1-16x16-999999.svg" /> <img align="right" title="Share on Facebook" src="https://docs.cloudposse.com/images/ionicons/social-facebook-outline-2.0.1-16x16-999999.svg" /> <img align="right" title="Share on Reddit" src="https://docs.cloudposse.com/images/ionicons/social-reddit-outline-2.0.1-16x16-999999.svg" /> <img align="right" title="Share on LinkedIn" src="https://docs.cloudposse.com/images/ionicons/social-linkedin-outline-2.0.1-16x16-999999.svg" /> <img align="right" title="Share on Twitter" src="https://docs.cloudposse.com/images/ionicons/social-twitter-outline-2.0.1-16x16-999999.svg" />
It's 100% Open Source and licensed under the APACHE2.
Usage
Running
Refer to the Environment Variables section below to tune how the bastion
operates.
$ docker run -p 1234:22 cloudposse/bastion:latest
Building
$ git clone https://github.com/cloudposse/bastion.git
$ cd bastion
$ make docker:build
Testing
Run basic connection tests
$ make test
Configuration
Recommendations
- Do not allow
root
(orsudo
) access to this container as doing so would allow remote users to manipulate audit-logs in/var/log/sudo-io
- Use the bastion as a "jump host" for accessing other internal systems rather than installing a lot of unnecessary stuff, which increases the overall attack surface.
- Sync the contents of
/var/log/sudo-io
to a remote, offsite location. If using S3, we recommend enabling bucket-versioning. - Use `github-authorized-keys to automatically provision users; or use the Helm chart.
- Bind-mount
/etc/passwd
,/etc/shadow
and/etc/group
into the container as read-only - Bind-mount
/home
into container; the bastion does not manage authorized keys
Environment Variables
The following tables lists the most relevant environment variables of the bastion
image and their default values.
Duo Settings
Duo is a enterprise MFA provider that is very affordable. Details here: https://duo.com/pricing
ENV | Description | Default |
---|---|---|
MFA_PROVIDER | Enable the Duo MFA provider | duo |
DUO_IKEY | Duo Integration Key | |
DUO_SKEY | Duo Secret Key | |
DUO_HOST | Duo Host Endpoint | |
DUO_FAILMODE | How to fail if Duo cannot be reached | secure |
DUO_AUTOPUSH | Automatically send a push notification | yes |
DUO_PROMPTS | How many times to prompt for MFA | 1 |
Google Authenticator Settings
Google Authenticator is a free & open source MFA solution. It's less secure than Duo because tokens are stored on the server under each user account.
ENV | Description | Default |
---|---|---|
MFA_PROVIDER | Enable the Google Authenticator provider | google-authenticator |
Enforcer Settings
The enforcer ensures certain conditions are satisfied. Currently, these options are supported.
ENV | Description | Default |
---|---|---|
ENFORCER_ENABLED | Enable general enforcement | true |
ENFORCER_CLEAN_HOME_ENABLED | Erase dot files in home directory before starting session | true |
Slack Notifications
The enforcer is able to send notifications to a slack channel anytime there is an SSH login.
ENV | Description | Default |
---|---|---|
SLACK_ENABLED | Enabled Slack integration | false |
SLACK_HOOK | Slack integration method (e.g. pam , sshrc ) | sshrc |
SLACK_WEBHOOK_URL | Webhook URL | |
SLACK_USERNAME | Slack handle of bot (defaults to short-dns name) | |
SLACK_TIMEOUT | Request timeout | 2 |
SLACK_FATAL_ERRORS | Deny logins if slack notification fails | true |
SSH Auditor
The SSH auditor uses sudosh
to record entire SSH sessions (stdin
, stdout
, and stderr
).
ENV | Description | Default |
---|---|---|
SSH_AUDIT_ENABLED | Enable the SSH Audit facility | true |
This will require that users login with the /usr/bin/sudosh
shell.
Update user's default shell by running the command: usermod -s /usr/bin/sudosh $username
. By default, root
will automatically be updated to use sudosh
.
Use the sudoreplay
command to audit/replay sessions.
User Accounts & SSH Keys
The bastion
does not attempt to manage user accounts. We suggest using GitHub Authorized Keys to provision user accounts and SSH keys. We provide a chart of how we recommend doing it.
Extending
The bastion
was written to be easily extensible.
You can extend the enforcement policies by adding shell scripts to etc/enforce.d
. Any scripts that are +x
(e.g. chmod 755
) will be executed at runtime.
Thanks
- @neochrome, for providing a great basic bastion built on top of Alpine Linux
- @aws, for providing detailed instructions on how to do SSH session logging.
- @duo, for providing excellent documentation
- @google for contributing Google Authenticator to the Open Source community
Quick Start
Here's how you can quickly demo the bastion
. We assume you have ~/.ssh/authorized_keys
properly configured and your SSH key (e.g. ~/.ssh/id_rsa
) added to your SSH agent.
$ docker run -it -p 1234:22 \
-e MFA_PROVIDER=google-authenticator \
-v ~/.ssh/authorized_keys:/root/.ssh/authorized_keys \
cloudposse/bastion
Now, in another terminal you should be able to run:
$ ssh root@localhost -p 1234
The first time you connect, you'll be asked to setup your MFA device. Subsequently, each time you connect, you'll be prompted to enter your MFA token.
Help
Got a question? We got answers.
File a GitHub issue, send us an email or join our Slack Community.
DevOps Accelerator for Startups
We are a DevOps Accelerator. We'll help you build your cloud infrastructure from the ground up so you can own it. Then we'll show you how to operate it and stick around for as long as you need us.
Work directly with our team of DevOps experts via email, slack, and video conferencing.
We deliver 10x the value for a fraction of the cost of a full-time engineer. Our track record is not even funny. If you want things done right and you need it done FAST, then we're your best bet.
- Reference Architecture. You'll get everything you need from the ground up built using 100% infrastructure as code.
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Slack Community
Join our Open Source Community on Slack. It's FREE for everyone! Our "SweetOps" community is where you get to talk with others who share a similar vision for how to rollout and manage infrastructure. This is the best place to talk shop, ask questions, solicit feedback, and work together as a community to build totally sweet infrastructure.
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Join us every Wednesday via Zoom for our weekly "Lunch & Learn" sessions. It's FREE for everyone!
Contributing
Bug Reports & Feature Requests
Please use the issue tracker to report any bugs or file feature requests.
Developing
If you are interested in being a contributor and want to get involved in developing this project or help out with our other projects, we would love to hear from you! Shoot us an email.
In general, PRs are welcome. We follow the typical "fork-and-pull" Git workflow.
- Fork the repo on GitHub
- Clone the project to your own machine
- Commit changes to your own branch
- Push your work back up to your fork
- Submit a Pull Request so that we can review your changes
NOTE: Be sure to merge the latest changes from "upstream" before making a pull request!
Copyright
Copyright © 2017-2023 Cloud Posse, LLC
License
See LICENSE for full details.
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
https://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
Trademarks
All other trademarks referenced herein are the property of their respective owners.
About
This project is maintained and funded by Cloud Posse, LLC. Like it? Please let us know by leaving a testimonial!
We're a DevOps Professional Services company based in Los Angeles, CA. We ❤️ Open Source Software.
We offer paid support on all of our projects.
Check out our other projects, follow us on twitter, apply for a job, or hire us to help with your cloud strategy and implementation.
Contributors
<!-- markdownlint-disable --><br/>Erik Osterman | <br/>Marji Cermak |
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