Multiple Ways to Secure SSH Server

Different Ways to Secure SSH Server

• By changing Default SSH Port.
• Using Strong Password.
• Using Public Key.
• Allowing a single IP to Log in.
• Disabling Empty Password.
• Using Protocol 2 for SSH Server.
• By Disabling X11 Forwarding.
• Setting an Idle Timeout.

1. How do I make OpenSSH more secure?
2. How secure is an SSH server?
3. How do I restrict access to SSH?
4. Is SSH hack possible?
5. Should I change my SSH port?
6. Is it safe to forward ssh port?
7. What is the ssh command?
8. What is the difference between SSH and telnet?
9. What is the difference between SSL and SSH?
10. Which users can SSH?
11. How do I restrict a login in Linux?
12. Is ssh insecure?
13. Is it possible to brute force SSH key?
14. How often should SSH keys be changed?

How do I make OpenSSH more secure?

10 Steps to Secure Open SSH

1. Strong Usernames and Passwords. ...
2. Configure Idle Timeout Interval. ...
3. Disable Empty Passwords. ...
4. Limit Users' SSH Access. ...
5. Only Use SSH Protocol 2. ...
6. Allow Only Specific Clients. ...
7. Enable Two-Factor Authentication. ...
8. Use Public/Private Keys for Authentication.

How secure is an SSH server?

SSH keys allow you to make connections without a password that are—counterintuitively—more secure than connections that use password authentication. When you make a connection request, the remote computer uses its copy of your public key to create an encrypted message that is sent back to your computer.

How do I restrict access to SSH?

HOWTO: Restrict ssh access by IP Address and/or username

1. Edit the /etc/hosts. allow file to include these lines, assuming your machine is on the 192.168. ...
2. Edit your /etc/hosts.deny file to include this line: sshd,sshdfwd-X11:ALL.
3. These lines refuse SSH connections from anyone not in the IP address blocks listed.

Is SSH hack possible?

SSH is one of the most common protocols in use in modern IT infrastructures, and because of this, it can be a valuable attack vector for hackers. One of the most reliable ways to gain SSH access to servers is by brute-forcing credentials.

Should I change my SSH port?

Changing the port only stops automatic attacks against your SSH and some script kiddies. If someone was targeting you then they could fine the new SSH port. The advantage is that it stops failed login attempts in your logs.

Is it safe to forward ssh port?

SSH port forwarding is not dangerous by itself, however, its safety depends on the service at the target port. Some have suggested that the safety of port forwarding is dependent on how strong your firewall is and its level of internal and external protection.

What is the ssh command?

ssh stands for “Secure Shell”. It is a protocol used to securely connect to a remote server/system. ... ssh command consists of 3 different parts: ssh command instructs the system to establish an encrypted secure connection with the host machine. user_name represents the account that is being accessed on the host.

What is the difference between SSH and telnet?

Telnet is the standard TCP/IP protocol for virtual terminal service, while SSH or Secure Shell is a program to log into another computer over a network to execute commands in a remote machine. Telnet transfers the data in plain text while in SSH data is sent in encrypted format via a secure channel. ...

What is the difference between SSL and SSH?

The key difference between SSH vs SSL is that SSH is used for creating a secure tunnel to another computer from which you can issue commands, transfer data, etc. On the other end, SSL is used for securely transferring data between two parties – it does not let you issue commands as you can with SSH.

Which users can SSH?

Any user with a valid shell in /etc/passwd can potentially login. If you want to improve security, set up SSH with public-key authentication (there is lots of info on the web on doing this), install a public key in one user's ~/. ssh/authorized_keys file, and disable password-based authentication.

How do I restrict a login in Linux?

Limit User's Access To The Linux System Using Restricted Shell. First, create a symlink called rbash from Bash as shown below. The following commands should be run as root user. Next, create an user called "ostechnix" with rbash as his/her default login shell.

Is ssh insecure?

SSH is not typically considered insecure in and of itself but it is an administrative protocol and some organizations require two or more layers of control to get access to an administrative console. For example connecting via a VPN first then opening an SSH session which connects through that VPN.

Is it possible to brute force SSH key?

SSH Brute force attacks are here to stay. ... Not only for SSH, but we often see brute forces via FTP or to admin panels (Plesk, WordPress, Joomla, cPanel, etc). As for protecting your site against brute force attacks, the first option is to use SSH keys (and disable password authentication).

How often should SSH keys be changed?

5 Answers. Yes, strictly speaking it is recommended to expire SSH keys after a while (this could depend of the key length, vulnerabilities found in the key generator, etc.). However such mechanism was not foreseen by SSH. And it is cumbersome to go to every possible remote hosts and delete the public key.