Lab #0.5: Care and Feeding of Your VM

ECE455
Lab #0.5: Care and Feeding of Your VM
Name: ___________________________________________
This is an introduction to your new personal Cyber Security VM.
$ man ssh
SSH(1) BSD General Commands Manual SSH(1)
NAME
ssh — OpenSSH SSH client (remote login program)
Overview
Goals
• Log into your VM
• Change password
• Generate and exchange SSH keys for password-less logins
Grading & Submission
• Authentication check (I will make sure you have secured your VM)
• Submit a copy of your SSH public key to me via email
Things to think about
• SSH keys what do these represent?
• What does the -t ed25519 option actually do? Why use this?
• Checkout sshd_config. What can you do with this? Can you make SSH safer or more dangerous?
• Checkout /var/log/auth.log on your VM. What do you see here? What if you grep for “sshd”?
Cyber Security VMs
For your convenience we have configured a few VMs in the ee.cooper.edu subdomain.
Student Name VM Hostname IP
Cucchiara, Paul M. cybersecn1 199.98.27.226
Gartenberg, Rebecca cybersecn2 199.98.27.172
Jaro, Sophie cybersecn3 199.98.27.201
Koszykowski, Mark C. cybersecn4 199.98.27.217
Lam, Jonathan cybersecn5 199.98.27.200
Lee, Richard cybersecn6 199.98.27.231
Li, Shine cybersecn7 199.98.27.235
Liu, Allister cybersecn8 199.98.27.44
Park, Donghyun cybersecn9 199.98.27.43
Song, Theo cybersecn10 199.98.27.229
Tsarev, Daniel cybersecn11 199.98.27.225
Wang, Bonny cybersecn12 199.98.27.189
Zhang, Victor cybersecn13 199.98.27.86
You may log into these with:
Username:cooperhat
Password:changeme
Change your password
After logging in please change the password and create your own username:
$ passwd
Changing password for user cooperhat
$ adduser gitzel
Adding user `gitzel’ …
Adding new group `gitzel’ (1001) …
Adding new user `gitzel’ (1001) with group `gitzel’ …
Creating home directory `/home/gitzel’ …
Copying files from `/etc/skel’ …
Exchange SSH keys
Exchanging SSH keys will allow for password-less logins.
First generate your keys:
$ ssh-keygen -t ed25519
Generating public/private ed25519 key pair.
Enter file in which to save the key (/afs/ee.cooper.edu/user/g/gitzel/.ssh/id_ed25519):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /afs/ee.cooper.edu/user/g/gitzel/.ssh/id_ed25519.
Your public key has been saved in /afs/ee.cooper.edu/user/g/gitzel/.ssh/id_ed25519.pub.
This will place your public and private key pairs in the location you specified protected by an optional
password.
Then copy your public key to the remote server:
$ ssh-copy-id -i .ssh/id_ed25519.pub [USER]@[VM_ADDR]
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: “.ssh/id_ed25519.pub”
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are
already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed — if you are prompted now it is to
install the new keys
gitzel@199.98.27.210’s password:
bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
Number of key(s) added: 1
You should now be able to SSH into the server without a password.
To further harden your VM, remove the password login option. Warning! You will only be able to SSH into
the VM from a host that has a copy of you SSH keys.
$ su cooperhat
…
$ sudo vim /etc/ssh/sshd_config
…
[Within VIM or some text editor]
# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication no