Differences

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--- securing_remote_ssh_access [2013/01/05 06:00] – [Disable Root Logins] 206.174.106.118
+++ securing_remote_ssh_access [2013/01/05 06:06] – [Disable Root Logins] 206.174.106.118
@@ Line 15: / Line 15: @@
 By default with SSH you can login directly using the root username and password. Since it is a given that every Linux and Unix system has a user called root, this is the obvious choice for an attacker to use and it gives them super user access with no further effort.
-We can disable logging in directly as root via SSH, after this change you'll need to login as a standard user and if root privileges are needed issue ''su -'', you'll then be prompted for the root password. Once you have finished ''Ctrl D'' to exit back to the previous user. From the console - that is the keyboard and monitor connected to your node you can still login directly as root.
+We can disable logging in directly as root via SSH, after this change you'll need to login as a standard user and if root privileges are needed issue ''su -'', you'll then be prompted for the root password. Once you have finished ''Ctrl D'' to exit back to the previous user. From the console - that is the keyboard and monitor connected to your node, you can still login directly as root.
   - As root edit ''/etc/ssh/sshd_config'', find and change the ''PermitRootLogin'' option to read ''PermitRootLogin no''. Save, and restart sshd with ''/etc/init.d/sshd restart''.
   - Now you can either set a password on the IRLP ''repeater'' user or add your own user account. To (re)set the repeater password as root issue the following command ''passwd repeater'' and follow the prompts. You will now use this username and password when using SSH to login.
+  - If you are doing this change remotely, open another connection and test logging in as repeater or with your own user account, and switching to the root account before you close your current session. Otherwise you could potentially lock your self out of the system until you can gain access to the console to straighten things out.
 It is also a good practice to avoid using the root account unless you really need to be the super user to do something, one typo can hose an entire system before you know it's even happened. I managed to wipe most of the file system on a Unix system once, luckily it was on a test system, and with the OS install CD and yesterdays backup tape in hand I had the system restored to its previous state with-in a couple hours. If you have no disaster recovery plan, you can spend hours or even days piecing a system back-together.