Make your home PC accessible from a cloud computer using ssh reverse

Inspired by MR. Robot Raspberry attack


First of all, you need a server with ssh access in the cloud, you can purchase a free one from amazon aws, let's call it mycloud

I want access my home pc (myhome) from my job pc (myjob).

First let's make myhome always connect to mycloud everytime it is connected to the internet. Since it's debian based linux, I write a script that I will call  connect2mycloud and save it into /etc/network/if-up.d/ directory

inside /etc/network/init.d/connect2mycloud type the following and save it

ssh -R 12345:localhost:22 clouduser@mycloud
#su -c "autossh -f -N -R 12345:localhost:22 clouduser@mycloud -oStrictHostKeyChecking=no" myhomeuser

For RedHat based create a file called 15-connect2mycloud in the directory /etc/NetworkManager/dispatcher.d/
and inside /etc/NetworkManager/dispatcher.d/15-connect2mycloud type the following and save it

if [ "$2" = "up" ]; then     
   ssh -R 12345:localhost:22 clouduser@mycloud 
   #su -c "autossh -f -N -R 12345:localhost:22 clouduser@mycloud -oStrictHostKeyChecking=no" myhomeuser

fi

Doing this every time myhome is connected to the internet it will create a ssh reverse connection from mycloud. So once I am logged into mycloud I can just do ssh -p 12345 localhost, then I will connect to myhome

Ok, now I'm at myjob pc, and want to connect to myhome directly with only one command

To achieve this you must create an entry in your ~/.ssh/config file with a proxy command
so in myjob  I add the following entry in ~/.ssh/config file like this

Host myhome

   User myuser

     ControlMaster auto

ControlPath /tmp/ssh-%r@%h:%p 

ProxyCommand ssh myuser@mycloud nc localhost 12345 2> /dev/null

Now to connect to myhome, I just run
# ssh myhome    
It will ask me mycloud and after myhome password in sequence, or nothing if I use public key

If you want to execute screen on remote host you need to  use -tt (alocate tty) like this
# ssh -tt myhome screen -dR

If you don't want to edit ssh config file use the command
# ssh -tt myuser@mycloud 'ssh  -tt localhost -p 12345'
you can also call screen reattach
# ssh -tt myuser@mycloud 'ssh  -tt localhost -p 12345'  screen -dR