SSH to AWS Instance without key pairs
SshAmazon Ec2Ssh KeysSsh Problem Overview
1: Is there a way to log in to an AWS instance without using key pairs? I want to set up a couple of sites/users on a single instance. However, I don't want to give out key pairs for clients to log in.
2: What's the easiest way to set up hosting sites/users in 1 AWS instance with different domains pointing to separate directories?
Ssh Solutions
Solution 1 - Ssh
Answer to Question 1
Here's what I did on a Ubuntu EC2
:
A) Login as root using the keypairs
B) Setup the necessary users and their passwords with
# sudo adduser USERNAME
# sudo passwd USERNAME
C) Edit /etc/ssh/sshd_config
setting
For a valid user to login with no key
PasswordAuthentication yes
Also want root to login also with no key
PermitRootLogin yes
D) Restart the ssh
daemon with
# sudo service ssh restart
just change ssh to sshd if you are using centOS
Now you can login into your ec2
instance without key pairs.
Solution 2 - Ssh
-
You should be able to change the ssh configuration (on Ubuntu this is typically in
/etc/ssh
or/etc/sshd
) and re-enable password logins. -
There's nothing really AWS specific about this - Apache can handle VHOSTS (virtual hosts) out-of-the-box - allowing you to specify that a certain domain is served from a certain directory. I'd Google that for more info on the specifics.
Solution 3 - Ssh
I came here through Google looking for an answer to how to setup cloud init to not disable PasswordAuthentication on AWS. Both the answers don't address the issue. Without it, if you create an AMI then on instance initialization cloud init will again disable this option.
The correct method to do this, is instead of manually changing sshd_config you need to correct the setting for cloud init (Open source tool used to configure an instance during provisioning. Read more at: https://cloudinit.readthedocs.org/en/latest/). The configuration file for cloud init is found at: /etc/cloud/cloud.cfg
This file is used for setting up a lot of the configuration used by cloud init. Read through this file for examples of items you can configure on cloud-init. This includes items like default username on a newly created instance)
To enable or disable password login over SSH you need to change the value for the parameter ssh_pwauth. After changing the parameter ssh_pwauth from 0 to 1 in the file /etc/cloud/cloud.cfg bake an AMI. If you launch from this newly baked AMI it will have password authentication enabled after provisioning.
You can confirm this by checking the value of the PasswordAuthentication in the ssh config as mentioned in the other answers.
Solution 4 - Ssh
Recently, AWS added a feature called Sessions Manager to the Systems Manager service that allows one to SSH into an instance without needing to setup a private key or opening up port 22. I believe authentication is done with IAM and optionally MFA.
You can find out more about it here:
Solution 5 - Ssh
su - root
Goto /etc/ssh/sshd_config
vi sshd_config
Authentication:
PermitRootLogin yes
To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no
Change to no to disable tunnelled clear text passwords
PasswordAuthentication yes
:x!
Then restart ssh service
root@cloudera2:/etc/ssh# service ssh restart
ssh stop/waiting
ssh start/running, process 10978
Now goto sudoers files (/etc/sudoers).
User privilege specification
root ALL=(ALL)NOPASSWD:ALL
yourinstanceuser ALL=(ALL)NOPASSWD:ALL / This is the user by which you are launching instance.
Solution 6 - Ssh
AWS added a new feature to connect to instance without any open port, the AWS SSM Session Manager. https://aws.amazon.com/blogs/aws/new-session-manager/
I've created a neat SSH ProxyCommand script that temporary adds your public ssh key to target instance during connection to target instance. The nice thing about this is you will connect without the need to add the ssh(22) port to your security groups, because the ssh connection is tunneled through ssm session manager.
AWS SSM SSH ProxyComand -> https://gist.github.com/qoomon/fcf2c85194c55aee34b78ddcaa9e83a1
Solution 7 - Ssh
Amazon added EC2 Instance Connect
.
There is an official script to automate the process https://pypi.org/project/ec2instanceconnectcli/
pip install ec2instanceconnectcli
Then just
mssh <instance id>