SSH Over Local Network
Under a production installation post-install, the default way to gain SSH administrative access is over the Tor network. This provides a number of benefits:
Allows remote administration outside of the local network.
Provides anonymity to an administrator while logging into the SecureDrop servers.
Can mitigate against an attacker on your local network attempting to exploit vulnerabilities against the SSH daemon.
Most administrators will need SSH access during the course of running a SecureDrop instance and a few times a year for maintenance. So the potential shortfalls of having SSH over Tor are not usually a major issue. The cons of having SSH over Tor can include:
Slow and delayed remote terminal performance
Allowing SSH access from outside of your local network can be seen as a potential larger security hole for some organizations, particularly those with tight network security controls.
That being said, the default setting of only allowing SSH over Tor is a good fit for most organizations. If you happen to require SSH restricted to the local network instead please continue to read.
Configuring SSH for Local Access
It is important that your firewall is configured adequately if you decide you need SSH over the local network. The install process locks down access as much as possible with net restrictions, SSH keys, and two-factor authentication. However, you could still leave the interface exposed to unintended users if you did not properly follow our network firewall guide.
This setting will lock you out of SSH access to your instance if your Admin Workstation passes through a NAT in order to get to the SecureDrop servers. If you are unsure whether this is the case, please consult your firewall configuration or network administrator.
Whichever network you install from will be the one that SSH is restricted to post-install. This will come into play particularly if you have multiple network interfaces.
First, make sure your local SecureDrop environment is up-to-date and on the latest production release.
$ sudo apt update
$ cd ~/Persistent/securedrop
$ ./securedrop-admin update
$ ./securedrop-admin setup
The setting that controls SSH over LAN access is set during the
of the install. Below is an example of what the prompt will look like. You can
answer either ‘no’ or ‘false’ when you are prompted for
Enable SSH over Tor:
$ ./securedrop-admin sdconfig
Username for SSH access to the servers: vagrant
Local IPv4 address for the Application Server: 10.0.1.4
Local IPv4 address for the Monitor Server: 10.0.1.5
Hostname for Application Server: app
Hostname for Monitor Server: mon
Enable SSH over Tor (recommended, disables SSH over LAN). If you respond no, SSH will be available over LAN only: no
Then you’ll have to run the installation script:
$ ./securedrop-admin install
If you are migrating from a production install previously configured
with SSH over Tor, you will be prompted to re-run the
twice. This is due to the behind the scenes configuration changes being
done to switch between Tor and the local network.
Finally, re-configure your Admin Workstation as follows:
$ ./securedrop-admin tailsconfig
Assuming everything is working you should be able to gain SSH access as follows:
$ ssh app
$ ssh mon