SKA - SSH Key Authority

Please see the Security Advisories section below for a recently addressed security issue

A tool for managing user and server SSH access to any number of servers.

Features

• Easily manage SSH key access for all accounts on your servers.
• Manage user access and server-to-server access rules.
• Integrate with your LDAP directory service for user authorization.
• Automatically remove server access from people when they leave your team.
• Provides an easy interface for your users to upload their public keys.
• Designate server leaders and let them manage access to their own server.
• Create group-based access rules for easier management.
• Specify SSH access options such as command=, nopty etc on your access rules.
• All access changes are logged to the database and to the system logs. Granting of access is also reported by email.
• Be notified when a server becomes orphaned (has no active leaders).

Requirements

• Docker engine

Baremeteal requirements (old, deprecated, use docker if possible)

• An LDAP directory service
• Apache 2.2 or higher
• PHP 5.6 or higher
• Composer
• PHP JSON extension
• PHP LDAP extension
• PHP mbstring (Multibyte String) extension
• PHP MySQL extension
• PHP GMP extension (not strictly needed, but a big performance improvement)
• MySQL (5.5+), Percona Server (5.5+) or MariaDB database

Installation

0. Install the Docker Engine (if not installed already)

1. Clone the repo.

2. Copy docker-compose.yml.example to docker-compose.yml and configure it.

3. Write initial configuration file according to config/config.ini.example

4. Generate an SSH key pair to synchronize with. SSH Key Authority will expect to find the files next to the config.ini file as config/keys-sync and config/keys-sync.pub for the private and public keys respectively. Be careful to use PEM format.

   ssh-keygen -b 4096 -m pem -f config/keys-sync

Baremeteal install (old, deprecated, use docker if possible)

1. Clone the repo somewhere outside of your default Apache document root.

2. Install the dependencies via composer:

   composer install
   

3. Add the following directives to your Apache configuration (eg. virtual host config):

   DocumentRoot /path/to/ska/public_html
   DirectoryIndex init.php
   FallbackResource /init.php
   

4. Create a MySQL user and database (run in MySQL shell):

   CREATE USER 'ska-user'@'localhost' IDENTIFIED BY 'password';
   CREATE DATABASE `ska-db` DEFAULT CHARACTER SET utf8mb4;
   GRANT ALL ON `ska-db`.* to 'ska-user'@'localhost';
   

5. Copy the file config/config-sample.ini to config/config.ini and edit the settings as required.

6. Set up authnz_ldap for your virtual host (or any other authentication module that will pass on an Auth-user variable to the application).

7. Set scripts/ldap_update.php and scripts/supervise_external_keys.php to run on a regular cron job.

8. Generate an SSH key pair to synchronize with. SSH Key Authority will expect to find the files as config/keys-sync and config/keys-sync.pub for the private and public keys respectively. Be careful to use PEM format.

   ssh-keygen -b 4096 -m pem -f config/keys-sync

9. Install the SSH key synchronization daemon. For systemd:

   1. Copy services/systemd/keys-sync.service to /etc/systemd/system/
   2. Modify ExecStart path and User as necessary. If SSH Key Authority is installed under /home, disable ProtectHome.
   3. systemctl daemon-reload
   4. systemctl enable keys-sync.service

   for sysv-init:

   1. Copy services/init.d/keys-sync to /etc/init.d/
   2. Modify SCRIPT path and USER as necessary.
   3. update-rc.d keys-sync defaults

Usage

Anyone in the LDAP group defined under admin_group_cn in config/config.ini will be able to manage accounts and servers.

Key distribution

SSH Key Authority distributes authorized keys to your servers via SSH. It does this by:

1. Connecting to the server with SSH, authorizing as the keys-sync user.
2. Writing the appropriate authorized keys to named user files in /var/local/keys-sync/ (eg. all authorized keys for the root user will be written to /var/local/keys-sync/root).

This means that your SSH installation will need to be reconfigured to read authorized keys from /var/local/keys-sync/.

Please note that doing so will deny access to any existing SSH public key authorized in the default ~/.ssh directories.

Under OpenSSH, the configuration changes needed are:

AuthorizedKeysFile /var/local/keys-sync/%u
StrictModes no

StrictModes must be disabled because the files will all be owned by the keys-sync user.

The file /var/local/keys-sync/keys-sync must exist, with the same contents as the config/keys-sync.pub file in order for the synchronization daemon to authenticate.

You can also use Install SKA management.sh convenience script that is part of this repo, but it isn't foolproof and it could lock you out so you're using it purely on your own risk.

Screenshots

Login page overview

Homepage overview

Server listing

Server account access management

Activity log

Getting started guide for new users

Security advisories

• SKA security advisory: SSH port redirection attack
• SKA security advisory: insufficient validation of group access rule edit privileges

License

Copyright 2013-2017 Opera Software Modifications Copyright 2021 Leitwerk AG Maintanence, Modifications and Improvements by Msprg

Licensed 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

http://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.