When using OpenSSH server (sshd) and client (ssh), what are all of the default / program preferred ciphers, hash, etc. (security related) and their default options (such as key length)?
For various reasons you might want to execute commands via SSH, using PowerShell. Presented here is a module with functions (that work like cmdlets or commands) for running commands via SSH on remote hosts such as Linux or Unix computers, VMware ESX(i) hosts or network equipment such as routers and switches that support SSH. It seems to work very well against OpenSSH-type servers.The module uses the which you can find on GitHub (formerly CodePlex). Also see the below where I've bundled the DLLs I've tested with.Starting with the good news about VMware: ESX(i) 4.x seems to be supported.However, I've found that when I try to connect to VMware ESXi 5.x using this module/library, using a password, I get the error 'Unable to connect to 192.168.1.103: Exception calling 'Connect' with '0' argument(s): 'No suitable authentication method found to complete authentication.' So it appears the authentication method ESXi implements isn't supported by the SSH.NET library, or maybe the other way around. The developers suggest an approach. I have tested this, but I'm getting an unexpected error related to the event handler.The code I'm using and error I'm getting is what the poster 'Jaykul' describes somewhere near the bottom of.Using a key will, however, work.
Given that, I suppose using this module to add keys to hosts running 4.x might be a good idea before upgrading them to 5.x to avoid manual labour (except the keys seem to be cleared on upgrade?).The majority of this was written in a couple of days and must be considered beta - but as of November 2017 this module has been downloaded over 80,000 times, and I've not heard much about bugs beyond wanting to be able to use key files in the current directory without using a full path (this is now supported in the 'SCP add-on version'). I've realized a few design decisions were quite poor, but rewriting seems daunting. This project is now also in the PowerShell gallery version (the best one, it supports PScredentials objects, etc.).I should also mention that importing private keys created with Putty will not work, as the Putty developer apparently uses a different key format standard than (most of) the rest of the world. The OpenSSH key format is currently supported, but the Putty key format might be supported later if the developers implement it.
There's a thread about it in the discussion forums on their CodePlex page. Oh, and PuttyGen.exe can save/export keys in OpenSSH format if you tell it to.Enjoy!
IntroductionSSH is a truly great and secure protocol. We all know we should be using it instead of telnet right. Right, but are you using all of its amazing abilities? Probably not is my guess, cause I wasn’t for quite some time. SSH on the ASA is a fairly simple affair configured the default way, with users, passwords and restricting ssh internet access to specific IP addresses.
That works, it needs no real explanation. What does need explanation however is the use of SSH key pairs. Now when we talk about SSH, I’m talking about version 2. Version 1 has holes. Version 2 does not. Google it.Certificate CreationFirst step is to disable SSH v1 on your ASA(config)#ssh version 2That was simple. Now take a look at the results:#sh sshssh secure copy: ENABLEDTimeout: 60 minutesVersion allowed: 2 255.255.255.0 insideGreat, the first part is done.
Now there are a great many SSH programs available but the one everyone knows and it is of course completely free, is PuTTY. You can get PuTTY here:I suggest on windows going with the installer for everything. To configure PuTTY to login with a username and password is easy but to use key pairs is slightly more involved.
Firstly you need to generate a PuTTY key pair. To do this open PuTTYgen.Generate the key as an SSH-2 RSA key pair. Now the default is 1024 bits in PuTTY, this can be safely doubled for increased security and all systems these days would cope without issue with a key this size. Now there are some options to create a comment, which you can use to track which PC the key is for. (I recommend a key pair per client device.
Asa Keygen Ssg Katherine Lee
Use one key for each device you use to access routers, switches, servers etc.) There is also the option to configure a passphrase. This is an extra layer of security so if your private keys were compromised it would buy you some invaluable time to replace them. You just need to save the private key which contains both the public and private keys within it in a sensible location. You can also save the public key which is what you will use on the ASA or any other SSH server hosting device. The public key is public in that you can give it to any old weirdo and in itself is useless. The private key is private in that you should guard it with your life! (Not quite but don’t transfer it about, leave it on your PC only, this is why I mentioned to have a key per device)ASA ConfigurationNow for the ASA configuration.
Asa Keygen Ssg Katherine Johnson
So the default setup for a user on the ASA is as follows:username johndoe password ReA!!y@w3som3Pa££w07d!Now this password is no mean feat to remember although everyone is using password managers anyway, but still, inconvenient to have to keep entering it.