> >A switch like on those 1.44'' floppy discs would be good...
> >But then software/OS updates would require physical access to the box...
>
> For this app, the problem is that there might indeed be physical
> tampering with the box despite some reasonable efforts to lock it up.
If the box is sub
--- Mike Tancsa <[EMAIL PROTECTED]> wrote:
> >But what if the trojan copies its files to the RAM disc and waits for this
> >sha256 binary showing up? And then, when it is there, it removes its
> >changes on
> >the hard disc (those changes certainly must be in unused (formerly zeroed)
> >areas of
At 04:45 PM 11/07/2006, R. B. Riddick wrote:
--- Poul-Henning Kamp <[EMAIL PROTECTED]> wrote:
> Arming a trojan to just do 'sleep 145 ; echo "sha256 = 0248482..."'
> when you thing you're running sha256 would be trivia.
>
But what if the trojan copies its files to the RAM disc and waits for this
--- Chuck Swiger <[EMAIL PROTECTED]> wrote:
> That suggestion is a very good point, although trying to find a single
> trojaned image which matches several checksum methods is supposed to be a
> highly difficult task.
>
If the hash function is cryptographically secure, even a single such hash
fu
At 04:34 PM 11/07/2006, Ruslan Ermilov wrote:
> >
> With respect to prepending a random salt to the image, can you expand
> what you mean ?
>
It means that every time you want to checksum it, you send some
random bits to be prepended to the image, then compute the
checksum(s). You then do the sa
In message <[EMAIL PROTECTED]>, "R. B. Rid
dick" writes:
>Wasn't is usual some years ago to switch the boot disc hardware to "read only"
>mode?
Some CF cards have that.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer
--- Poul-Henning Kamp <[EMAIL PROTECTED]> wrote:
> Arming a trojan to just do 'sleep 145 ; echo "sha256 = 0248482..."'
> when you thing you're running sha256 would be trivia.
>
But what if the trojan copies its files to the RAM disc and waits for this
sha256 binary showing up? And then, when it is
On Tue, Jul 11, 2006 at 04:18:19PM -0400, Mike Tancsa wrote:
> At 04:05 PM 11/07/2006, Poul-Henning Kamp wrote:
> >In message <[EMAIL PROTECTED]>, Chuck Swiger writes:
> >
> >>Checksumming the device image is a fine way of checking the
> >integrity of it,
> >>assuming it is read-only. The only th
Poul-Henning Kamp wrote:
In message <[EMAIL PROTECTED]>, Chuck Swiger writes:
Checksumming the device image is a fine way of checking the integrity of it,
assuming it is read-only. The only thing you might want to do is use two or
three checksum algorithms (ie, use sha256 and md5 and something
In message <[EMAIL PROTECTED]>, Mike Tancsa writes:
>With respect to prepending a random salt to the image, can you expand
>what you mean ?
If you just run sha256 on the disk image, and the attacker
finds out, he will just run sha256 himself and record the result.
Arming a trojan to just do 'sl
At 04:05 PM 11/07/2006, Poul-Henning Kamp wrote:
In message <[EMAIL PROTECTED]>, Chuck Swiger writes:
>Checksumming the device image is a fine way of checking the
integrity of it,
>assuming it is read-only. The only thing you might want to do is
use two or
>three checksum algorithms (ie, use
In message <[EMAIL PROTECTED]>, Chuck Swiger writes:
>Checksumming the device image is a fine way of checking the integrity of it,
>assuming it is read-only. The only thing you might want to do is use two or
>three checksum algorithms (ie, use sha256 and md5 and something else), so that
>someo
Mike Tancsa wrote:
[ ... ]
# ssh remote1.example.com "/tmp/rand-directory/dd if=/dev/ad2s1a
bs=4096k | /tmp/rand-directory/sha256"
120+1 records in
120+1 records out
505389056 bytes transferred in 169.727727 secs (2977646 bytes/sec)
955ebad583bfc0718eb28ac89563941407294d5c61a0c0f35e3773f029cc068
We have a number of Soekris devices that we will be deploying
remotely in semi- hostile physical environments. The remote links
are dialup so I dont have a lot of bandwidth available. I want to do
integrity checks of the images so that I can detect any tampering of
the flash image.
If I
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