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Date:      Wed, 22 Jul 1998 08:53:47 -0600
From:      Brett Glass <brett@lariat.org>
To:        ben@rosengart.com
Cc:        Jim Shankland <jas@flyingfox.com>, ahd@kew.com, leec@adam.adonai.net, security@FreeBSD.ORG
Subject:   Re: hacked and don't know why
Message-ID:  <199807221453.IAA03997@lariat.lariat.org>
In-Reply-To: <Pine.GSO.4.00.9807220227001.4886-100000@echonyc.com>
References:  <199807220613.AAA26581@lariat.lariat.org>

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In that case, we have an as-yet-diagnosed bug in the system. We
really experienced disk corruption -- especially of directories --
during the QPopper buffer overflow hack. Files got the wrong
owners and permissions; bitmaps were set wrong; the works. Every file
that was touched between the exploit and the next reboot was subject 
to these problems.

It's a good argument for stack protection.

--Brett


At 02:28 AM 7/22/98 -0400, Snob Art Genre wrote:
 
>On Wed, 22 Jul 1998, Brett Glass wrote:
>
>> The symptoms aren't hard to understand. As I found out when we
>> were hit by the same hack, buffer overflow exploits also
>> hose memory.... The disk cache, kernel data, possibly even page tables
>> can be corrupted. Nothing's safe. If you do anything to your file
>> system before rebooting, you can wind up with corrupted directories
>> and worse. This happened to us.
>
>This doesn't sound correct.  Buffer overflows can give you unauthorized
>access to user memory, but shouldn't give you access to kernel memory at
>all.  Otherwise running "crashme" as root would have more effect than it
>does (none).
>
>
> Ben
>
>"You have your mind on computers, it seems." 
> 

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