| Verify RHEL 8 disables the use of user namespaces with the following commands: |
Note: User namespaces are used primarily for Linux containers. If containers are in use, this requirement is not applicable.
$ sudo sysctl user.max_user_namespaces
user.max_user_namespaces = 0
If the returned line does not have a value of "0", or a line is not returned, this is a finding.
Check that the configuration files are present to enable this network parameter.
$ sudo grep -r user.max_user_namespaces /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf
/etc/sysctl.d/99-sysctl.conf: user.max_user_namespaces = 0
If "user.max_user_namespaces" is not set to "0", is missing or commented out, this is a finding.
If conflicting results are returned, this is a finding.