[Users] Dirty COW

[Scott Dowdle]

Greetings,

----- Original Message -----
> > According to the Red Hat bugzilla page
> > (https://bugzilla.redhat.com/show_bug.cgi?id=1384344#c13),
> > they claim that EL5 and EL6 are not vulnerable because
> > /proc/self/mem isn't writable by default.
> 
> According to German IT magazine heise.de this "default configuration"
> implies SELinux. Meaning: An SELinux rule protects /proc/self/mem
> against writing in the default RHEL configuration.
> 
> As OpenVZ requires SELinux to be set to "disabled" we don't seem to
> have that luxury.

Well, I'm sure quite a few people have SELinux disabled on RHEL/CentOS 5 and 6 hosts.

The OpenVZ Legacy system I tested happened to be running with an KVM VM on a RHEL 7.2 host with SELinux enabled and in enforcing mode... so maybe that's why it didn't work?

I don't see a difference between the perms on a stock EL6 host and an OpenVZ Legacy host... at least for DAC permissions:

-rw-------. 1 root root 0 Oct 21 17:59 /proc/self/mem

I would be nice to get confirmation from others who attempt the proof-of-concept.

TYL,
-- 
Scott Dowdle
704 Church Street
Belgrade, MT 59714
(406)388-0827 [home]
(406)994-3931 [work]