Re: Digital Armaments Security Advisory 20.01.2007: Grsecurity Kernel PaX Vulnerability
Hi,
quoting grsec developer: "Using the RBAC system's PaX flag support to enforce
system-wide MPROTECT enabling could have prevented triggering of the bug, since
it requires the creation of an executable stack to trigger the vma mirroring
bug."
I 've tested the exploit on 2.6 kernel in an Alpha platform with MPROTECT RBAC
protection activated -wich is our default setting :-)- and it doesn't work...
hugo@alpha ~ $ ./xploit
mprotect map1 base: Permission denied
run chpax -m on this executable
Moreover, even without MPROTECT activated it is important to remenber that OS
security must never rely on a single layer... a well-configured Grsec system
will render very difficult to exploit it -nor at least with a direct vector-.
On Grsec case, there are some configurations can help prevent/difficult the
exploitation: aggressive TPE (Trusted Path Execution) configuration + tight
RBAC policy + Network Protections will make a pain to exploit this, even
locally.
Regards,