auditd software package provides User space tools for security auditing, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install auditd
auditd is installed in your system.
Make ensure the auditd package were installed using the commands given below,
$ sudo dpkg-query -l | grep auditd *
You will get with auditd package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Administration Utilities |
| Package | auditd |
| Version | 1:2.4-1+b1 |
| Description | User space tools for security auditing |
| Sub Section | admin |