Again its no networkstack security stuff, and I am not shure if the enterprise linux systems have this bugs, and in many cases you can depend on that the users you gave a useraccount and have access to your intranet, are not attacking you. As example I had a job interview on a university, ok they use ubuntu so worst case it seems, but there only have pre-doctors access you can basicly think that they are not attackers. they have better stuff to do, and even if, if they attack stuff when they logged in with their accounts it is probably easy to find out who did damage stuff.
So there is maybe a reason for distries like debian and enterprise linuxes, if you have to update all 2 months to a new distri in a production environment you should maybe not hope this distros are multiuser-secure... I mean they should be secure for single-user systems... thats what desktop is primary, at thats the main target for systems like ubuntu.
And maybe offices where the users are no hackers but "moorhuhn" gamers.
I heared even from admins that they use systems (windows as clients in this case) that all 24 hours completly format the harddisks of the clients and copy over a windows image. So it seems at least windows is not (much) better in this sphere, it shure has a reason that they do that. not just for fun...