SSH Banners

I love SSH… like I really love it. It is pretty surprising that Windows only first had the ability to naively ssh only in the recent Windows 10 1803 build. That’s pretty sad. Just teste don my 1803 build.. nope… well I know I have done it before… anyway teh point I wanted to get here was more about SSH servers.

Now normally allowing SSH in to a system basically enables an SSH services on that system, making it the SSH server. Then you usually utilize a workstation, like the computer you usually use to navigate websites, like this one, to connect to that server with a piece of software (with Windows that’s usually Putty)… if I can get that dang native ssh to work (shakes fist)… anyway…

When you enable this service it is pretty powerful, depending on how you configure it, and what application is running the service. There are plenty of flavors to choose from (this is pretty common with Linux and open source). This is usually a good thing cause each one is scoped for a certain target audience. In my case I wanted to bring some old life back to my old Asus Router. I’ve been running DDWRT on it for a long time, and utilizing the simple command line interface (embedded linux) on a decent lil system only working as an AP otherwise, is a fun lil place to use IRC. 🙂 Find me on #Freenode (#Windows-Server, VMware, Cisco, Skullspace, FreeNAS) .

Now I figured if I was going to use this again, why not have some fun and re-do my loggin banner. Now in this case there are two things to consider:

1)  The Message of the Day (MOTD) – This displays as soon as a client connects before it asks for a username. In most cases this is a great place to place your unauthorized message. (In my case the MOTD was tied to a Read-Only FileSystem file, and I had no intentions of compiling my own build, so I decided to utilize the option to not display this).

2) The Login Banner – This message displays after you have specified a user name.

Now there can be many ways to customize your login banner, you may need to google the based on the SSH server you are using. In my case my router was utilizing dropbear lucky for me they have decent documentation.

In my case I simply had to create a simple text file pointing anywhere using the -b option: dropbear -b /somepath/banner.file

After I created my file I configured my startup script to point to my new banner file. Sure enough now when I log on I see this:

Boo yeah! Now that’s sweet.

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