Mastering Linux Security and Hardening

Creating a group and configuring the sshd_config file

With the exception of the slight difference in user-creation commands, this procedure works the same for either CentOS or Ubuntu. So, you can use either one of your virtual machines to follow along. We'll begin by creating an sftpusers group.

sudo groupadd sftpusers

Create the user accounts, and add them to the sftpusers group. We'll do both operations in one step. On your CentOS machine, the command for creating Max's account would be:

sudo useradd -G sftpusers max

On your Ubuntu machine, it would be:

sudo useradd -m -d /home/max -s /bin/bash -G sftpusers max

Open the /etc/ssh/sshd_config file in your favorite text editor. Find the line that says:

Subsystem sftp /usr/lib/openssh/sftp-server ...