Category Archives: SSH

Heartbleed & KRL

TweetOn 7th April, Heartbleed(CVE-2014-0160) shook both the tech-savvy world and the end-users alike. Majority of us use OpenSSL for one or the other reason. If it’s any version of OpenSSL from 1.0.1 through 1.0.1f, released between December 2011 & April 2014, then consider that you have already got compromised with security keys, private keys, passwords… Read More »

Two Factor Authentication in SSH

TweetMost of us used either password based authentication or public key based authentication while accessing server through ssh protocol.  Password based authentication is default authentication mechanism for ssh. We just have to enable sshd service on server.  For public key based authentication we have to generate private-public key pair.  We covered key based authentication in this… Read More »

Category: SSH

key based ssh authentication (Cygwin)

TweetWe all know now that Once installed, Cygwin opportune us to treat the local windows machine Linux Way (http://linuxmantra.com/2014/01/cygwin-openssh-mintty-ssh-client.html) . And a step forward is then to apply the very known public/Private key authentication on Cygwin in exact Linux-to-Linux way (explained @ http://linuxmantra.com/2009/09/ssh-using-privatepublic-key.html). So how actually is Cygwin treating my local machine… Now Using Cygwin-Openssh… Read More »

Category: SSH

Cygwin-openssh-mintty (SSH Client)

TweetNever thought, I would look for alternatives to Putty  & PSM: Putty Session Manager. Cygwin-Openssh-Mintty offers a brilliant option from amongst many other marvels like “MobaXterm” & SecureCRT (Licensed)… Most of us still connect to Linux Machine via ssh-client on a Windows/Mac, to say atleast in office. And I’m no exception. For this I depend… Read More »

Category: SSH

>Reverse SSH Tunnel

Tweet> I already discussed about SSH tunnel few days back in my post http://linuxinterviews.blogspot.com/2010/11/ssh-tunneling.html. Reverse SSH Tunnel can be used to connect office computer from home computer. Suppose you issued following command on your office computer.   root#ssh -R 2048:localhost:22   In above given statement , home computer 2048 port become open to connect office… Read More »

Category: SSH

>SSH Tunneling

Tweet> SSH Tunneling is also known as SSH Port Forwarding. Using SSH Tunneling you can forward all traffic through the system on which you have ssh access. For example suppose you are inside a network in which port 25(smtp) is not allowed , and you need to send mail using smtp. The solution is SSH… Read More »

Category: SSH

>SSH Session Hacking

Tweet>SSH session can be hacked using MiTM(Man in The Middle) attack. This attack is known as ssh downgrade attack. Let us understand it. Suppose you are accessing machine C from machine A using ssh                 A——————————–>C Now suppose there is a machine B which come in middle and… Read More »

Category: SSH

>Why ssh sometime become slow ?

Tweet>Sometime you found that that ssh take more than 20 seconds before it ask for  login.The reason for the slow connections is that SSH is trying to use Kerberos, hangs for about 10 seconds, then tries public key authentication, hangs for about 10 seconds, and then finally prompts for password. By setting  the "GSSAPIAuthentication" option… Read More »

Category: SSH

>ssh using private/public key

Tweet>We can access other machine without putting password every time. ssh provide option to put user public key as authorized key on machine which user want to access without entering password every time. Following simple steps are required to do thisroot@machine1#ssh-keygen…(press enter whenever ask for passphrase) ssh-keygen generate private(id_rsa) and public key(id_rsa.pub) file for that… Read More »

Category: SSH