I assume that Selinux defaults, based on the documentation, mandate that basically all port operations would be blocked and logged as AVCs.
I have an SELinux enforcing enabled VM, created with Centos7 out of the box.
SELinux status: enabled SELinuxfs mount: /sys/fs/selinux SELinux root directory: /etc/selinux Loaded policy name: mls Current mode: enforcing Mode from config file: enforcing Policy MLS status: enabled Policy deny_unknown status: allowed Max kernel policy version: 31
However, I can start a webserver and bind it to port 1.
[vagrant@localhost ~]$ sudo python -m SimpleHTTPServer 1 Serving HTTP on 0.0.0.0 port 1 ...
Im assuming SElinux , with enforcing and no other modifications on a fresh OS would actually limit access to these sorts of operations (im just using port 1 as an example of how severe a security violation can be, because in general I thought at least low number ports would be blocked by default via selinux).