How To Setup SSH Keys

<div dir="ltr" style="text-align: left;" trbidi="on"> <h1 class="entry-title" itemprop="headline" style="background-color: #fdfdfd; box-sizing: border-box; font-family: proxima-nova, 'Helvetica Neue', Helvetica, Arial, sans-serif; line-height: 1.1; margin: 21px 0px 0px; text-align: center;"> <span style="color: red; font-size: x-large;"><u>Setup SSH Keys</u></span></h1> <div> <div style="text-align: justify;"> <span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">SSH keys are by far the most secure way of logging into your cloud server via SSH. Passwords can be eventually cracked using brute-force attacks if they are too easy. If they are complex passwords, they become very hard to remember and writing them down defeats the purpose of a password.</span></span></div> <div style="text-align: justify;"> <span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b>SSH </b>keys are nearly impossible to decipher using a brute force attack. If you generate an <a href="http://www.hackthesec.co.in/search/label/SSH">SSH key</a>, you will get a pair of two very long string of characters: a public and private key.</span></span></div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgB-K6lGsBayShpawfyJUyK-w_T51_O2aLcOec6JqeyVBVxXPjj0nI2Cip35_7ga-VRAx8sR10WxPBTb8_CEk1t46cedsUG3ZEc_I2G9EWYzmQ6TFMYjhoxyy9cXPxzdseba1rHUiD4DX9H/s1600/ssh_keys_setup-www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgB-K6lGsBayShpawfyJUyK-w_T51_O2aLcOec6JqeyVBVxXPjj0nI2Cip35_7ga-VRAx8sR10WxPBTb8_CEk1t46cedsUG3ZEc_I2G9EWYzmQ6TFMYjhoxyy9cXPxzdseba1rHUiD4DX9H/s1600/ssh_keys_setup-www.hackthesec.co.in.jpg" /></a></div> <div style="text-align: justify;"> <span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div> <div style="text-align: justify;"> <span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Public keys are stored on the server that you’re trying to login to, the only possible tool which could unlock this public key is the private key which will be stored with you. SSH uses this to verify your identity by making sure that your private key can unlock the public key installed on the server.</span></span></div> </div> <div style="text-align: justify;"> <span style="font-family: Verdana, Geneva, sans-serif;"><span style="line-height: 26px;"><div> <b><u><span style="color: #0b5394; font-size: large;">Create the <a href="http://www.hackthesec.co.in/search/label/SSH">SSH</a> key pairs</span></u></b></div> <div style="color: #222222; font-size: 15px;"> The first step is to generate the combination of the public and private key. This can easily be done by opening a terminal window on the machine you will be using to access the remote server (most likely your own workstation).</div> <div style="color: #222222; font-size: 15px;"> <br /></div> <div style="color: #222222; font-size: 15px;"> In this example, we will be using RSA keys. The default values should be the correct ones, so you can simply just press enter to accept the default values. However, you may choose to add a passphrase for additional protection.</div> <div style="color: #222222; font-size: 15px;"> <br /></div> <div style="color: #222222; font-size: 15px;"> The passphrase is a password which unlocks your private key, which means that in order for someone to gain access, they must have both the private key and your passphrase. You can opt to not using a passphrase if you do not want to type a password each time.</div> </span></span></div> <div style="text-align: justify;"> <pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; text-align: left; vertical-align: baseline;"><div style="text-align: justify;"> <span style="color: lime; font-family: Courier New, Courier, monospace; font-size: large;"><span style="line-height: 15.6px;">[root@hackthesec]# ssh-keygen -t rsa</span></span></div> <div style="text-align: justify;"> <span style="color: white; font-family: Courier New, Courier, monospace; font-size: large;"><span style="line-height: 15.6px;">Generating public/private rsa key pair.</span></span></div> <div style="text-align: justify;"> <span style="color: white; font-family: Courier New, Courier, monospace; font-size: large;"><span style="line-height: 15.6px;">Enter file in which to save the key (/Users/user/.ssh/id_rsa): test</span></span></div> <span style="color: white; font-family: Courier New, Courier, monospace; font-size: large;"><span style="line-height: 15.6px;">Enter passphrase (empty for no passphrase): </span></span><div style="text-align: justify;"> <span style="color: white; font-family: Courier New, Courier, monospace; font-size: large;"><span style="line-height: 15.6px;">Your identification has been saved in /Users/user/.ssh/id_rsa.</span></span></div> <span style="color: white; font-family: Courier New, Courier, monospace; font-size: large;"><span style="line-height: 15.6px;">Enter same passphrase again: </span></span><div style="text-align: justify;"> <span style="color: lime; font-family: Courier New, Courier, monospace; font-size: large;"><span style="line-height: 15.6px;">Your public key has been saved in /Users/user/.ssh/id_rsa.pub.</span></span></div> </pre> <div style="background-color: white; font-family: Verdana, Geneva, sans-serif; font-size: 12px; line-height: 19.2px;"> </div> </div> <div style="text-align: justify;"> <span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">As you see by the results of the command, we now have an <b>id_rsa</b> and <b>id_rsa.pub</b> file which contain your private and public key respectively. We can now distribute this public key to servers where we would like to use public key authentication.</span></span></div> <div style="text-align: justify;"> <span style="font-family: Verdana, Geneva, sans-serif;"><span style="line-height: 26px;"><div> <b><u><span style="color: #0b5394; font-size: large;">Installing Public Key</span></u></b></div> <div style="color: #222222; font-size: 15px;"> The SSH software stack comes with a useful little program called ssh-copy-id which facilitates the installation of <b>SSH keys</b> on your target server. All you have to do is run the following, replacing user and host by the appropriate information for your remote host.</div> </span></span></div> <div style="text-align: justify;"> <pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; text-align: left; vertical-align: baseline;"><div style="text-align: justify;"> <span style="font-size: large;"><span style="color: white; font-family: Courier New, Courier, monospace;"><span style="line-height: 15.6px;">[root@hackthesec]# </span></span><span style="line-height: 15.6px; text-align: left;"><span style="color: lime; font-family: Courier New, Courier, monospace;">ssh-copy-id</span><span style="color: white; font-family: Courier New, Courier, monospace;"> user@host</span></span></span></div> </pre> </div> <div style="text-align: justify;"> <span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">If your operating system does not have that command included, you can run the following command instead. If you get an error about your<b> .ssh</b> folder not existing, you should login to your server and create that folder by running <b>mkdir ~/.ssh.</b></span></span></div> <div style="text-align: justify;"> <div> <pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; text-align: left; vertical-align: baseline;"><div style="text-align: left;"> <span style="font-size: large;"><span style="color: white; font-family: Courier New, Courier, monospace;"><span style="line-height: 15.6px;">[root@hackthesec]# </span></span><span style="line-height: 15.6px; text-align: left;"><span style="color: lime; font-family: Courier New, Courier, monospace;">cat /Users/user/.ssh/id_rsa.pub</span><span style="color: white; font-family: Courier New, Courier, monospace;"> | ssh user@host "cat >> ~/.ssh/authorized_keys"</span></span></span></div> </pre> </div> </div> <div style="text-align: justify;"> <span style="color: #222222; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">From now on, you can SSH to the server and you will note that your server will not ask for any passwords at all. The only thing it may ask for is your passphrase if you have configured one for your private key.</span></span></div> <div style="text-align: justify;"> <a href="http://www.hackthesec.co.in/">hackthesec.co.in</a></div> </div>

How To Setup SSH Keys

Setup SSH Keys SSH keys are by far the most secure way of logging into your cloud server via SSH. Passwords can be eventually cracked u...

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