The hidepid option in RHEL has the value 0 by default. This implies that all data is visible to every user. The directory entries in /proc will remain visible but inaccessible when set to 1.
To keep the data hidden from /proc, set the value to 2.
Run the following command to instantly apply the changes.
# mount -o remount,rw,hidepid=2 /proc
For long-term adjustments, Add the hidepid=2 option to the proc filesystem in /etc/fstab and remount the partition by using the following mount command.
# mount -a
The /proc entry in /etc/fstab is shown below.
proc /proc proc hidepid=2 0 0
Every Linux distribution provides the default setting of revealing ReadOnly processes to other users. This is mostly about privacy and has nothing to do with security. The idea that a timesharing system would be an open community is outdated.
Use containerization if a process needs to run and presents a potential attack surface. It has its own PID namespace in addition to the network, mount, user, UTS (hostname and NIS domain name) namespaces, cgroup, and root file tree.
