unix - Why is it common for binary (ELF) SUID executables to also allow READ access? -

To take advantage of the proof-of-concept as part of the recent "Rohammer", read-voodoo-edem The tool was "ping"

and therefore my question - why do vengeance (especially the root) in various distributions make the executable readable as well as executable?

My speculation includes:

1. Use facility with "ldd"
2. Tri-veer or package-update checking software is non- To allow it to run as root
3. this
4. Cilinux can be used to make this irrelevant
5. lazy developers

(3), hiding the public distribution binary only gives a fig leaf of security - and (5) there are too many names.

is not a complete answer, but I found out that if I need to read route root programs They have been stored on an NFS server.

I should say again: The local file system was enough for the set-root programs on chmod 4711, but the required mode on the NFS 4755 .