Install libnss-rsbac2 by entering the following commands in the terminal:
sudo apt update sudo apt install libnss-rsbac2
RSBAC NSS module
RSBAC (Rule Set Based Access Control) is a kernel patch which adds several mandatory access models to the Linux kernel. These models can be used to enhance the security of a Linux system. . This package contains the RSBAC NSS module to use RSBAC User Management.