![]() Let's open the temporary file tmp]# cd ssh-mKX88v0Vlo]# ll In /tmp directory you may see something like that: tmp]# llĭrwx- 2 bastion bastion 4096 Sep 7 17:35 ssh-mKX88v0Vlo How to hack servers if you compromised bastion host? Track Target But do you really want to the risk when you have other options like Prox圜ommand? Hence, just use Prox圜ommand! I know the window of compromise is very small because it depends on how much time you are connected to the bastion host. As a result, all your server can be accessed. ![]() Imagine that your bastion server is compromised, If someone has sufficient permissions on your Linux server he/she will just use your socket info. It means that the socket will be set up so that someone may use this socket data to access your servers. Let's explain everything inside out: When you connect bastion host your glorious ssh-agent is forwarded.Because Agent forwarding is dangerous and it's consider considered harmful.Because you are using SSH Agent forwarding!.Is my server secure? And the answer is quite simple: Connect application server from the bastion ssh -p PORT Add your authentification key to ssh-agent ssh-add ~/.ssh/name_rsa Create config in ~/.ssh/config Host bast Let's talk about Prox圜ommand.īut wait, wait! I can write to you how to hack the server that uses Agent forwarding, that would be much easier to understand the difference! Let's hack!įor the basic steps: you can read my post here If you have an older version of OpenSSH which does not support ProxyJump (on the client side), then replace: ProxyJump bastion Example with Prox圜ommand instead of ProxyJump After the above deployment and verifying that everything work as intended, you should disallow password authentication on the 2 servers. Note: the above will work only if password authentication is still allowed. $ ssh-copy-id -i ~/.ssh/id_protected_lan.pub \ You can use (the $ sign is just to illustrate the prompt, do not type it): $ ssh-copy-id -i ~/.ssh/id_bastion.pub \ Of course you need to deploy the public keys to both bastion and srvC. KeeAgent or ssh-agent), but if it is not running then it will also work and ask you for each key passphrases. Finally the IdentityFile is optional if you use a local agent (e.g. For the users, you need to update the User for the correct login name on the Bastion and server C. In the HostName you need to put either IPs or real fully qualified domain name for your hosts. In the above example, "bastion" is an alias to your Bastion host and srvC is an alias to your server C. Then doing ssh srvC will connect you to C via B (bastion) without Agent Forwarding nor deploying the private key to the bastion. On your client computer you write a file under ~/.ssh/config with a similar content to bellow: Host bastion I would recommend to use Prox圜ommand (or even better ProxyJump as the syntax is easier but requires openssh 7.3+ I think on the client side), and you do not need to deploy private key on the Bastion, everything stays local. What is better? What about the alternative from the second link: Prox圜ommand, I understand it helps with the socket file issue, but still I think I have to enable TCP forwarding, so is it secure enough? Risk, so we recommend that you keep the default (disabled) setting This can be very useful but it is also a security TCP forward: Setting this value to true will enable TCP forwarding ![]() When setting up agent forwarding, a socket file is created on the forwarding host, which is the mechanism by which the key can be forwarded to the destination. For setting up agent forwarding, I need to allow TCP Forwarding. There to other instances in private subnets. Use SSH agent forwarding to connect first to the bastion and from Never place your SSH private keys on the bastion instance. We read that it's a bad idea to do that in a production environment. I need the bastion to automatically forward port 22 traffic to the VNC port, for my user only if possible but not 100% required.We need to SSH from A through B to C, using private key. I do not have root access on the bastion host.Īll of the solutions I've found so far involve SSHing via command line, not using VNC. Now my issues is I don't know how to get my bastion host to forward incoming port 22 for my user to the destination port 5905, in my case. My idea was to use TightVNC viewer and SSH tunnel through the bastion host to the GUI instance. Now I can only use port 22 to the bastion host but all outgoing connections are enabled. Problem: I need to be able to access that WebLogic server via internet browser through the bastion host. EC2 Instance (no graphical) with Docker running a WebLogic Server container.EC2 Instance with graphical desktop (private subnet).
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