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Re: MySQL (Linux) Heap Based Overrun PoC Zeroday
From: Jeffrey Walton <noloader () gmail com>
Date: Sun, 2 Dec 2012 17:19:16 -0500

On Sun, Dec 2, 2012 at 10:40 AM, king cope
<isowarez.isowarez.isowarez () googlemail com> wrote:
When you look into the heap and stack overrun the first obstacle to
exploit the bugs is that MySQL does not allow all plain 0 to 255
characters, this means the exploiter would have to use unicode
translation in order to exploit the bugs (therefore these are PoCs
only by now). If the exploiter managed to execute code on default
installs without your mentioned protections it might be possible to
circumvent them, to be honest I didn't have a look into these
optimizations and protections, it's hard enough to exploit it without
these restrictions applied.
No problem, thanks. Rodrigo pointed out a RO GOT (-z,relro) meant the
GOT would be safe, but other areas were still vulnerable on the heap
overflow. I think I'd take a hardened GOT and make the attacker move
on to the next weak area.

Its really a shame that high risk applications (such as those that
take input from the Internet) are still failing in these ways in 2012.
There's a lot of platform security available (and other hardening
techniques), but folks chose not to use them. It's  disappointing the
various security teams have not improved the situation (they are the
folks who should know, and should take a defensive posture).

Jeff

2012/12/1 Jeffrey Walton <noloader () gmail com>:
Hi Kingcope,

# As seen below $edx and $edi are fully controlled,
# the current instruction is
# => 0x83a6b24 <free_root+180>:   mov    (%edx),%edi
# this means we landed in a place where 4 bytes can be controlled by 4 bytes
# with this function pointers and GOT entries can be rewritten to
execute arbritrary code

Out of curiosity, is this exploitable when using hardened toolchain
settings? Specifically, -z,noexecheap, -z,now, and -z,relro? For
no-exec heaps., you need to be on Gentoo or other platforms which
offer the remediation.

Jeff

On Sat, Dec 1, 2012 at 4:26 PM, king cope
<isowarez.isowarez.isowarez () googlemail com> wrote:
(see attachment)

Cheerio,

Kingcope

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