[AusNOG] Preparing 100s of routers for resale

Karl Auer kauer at biplane.com.au
Thu Apr 12 19:51:53 EST 2012

On Thu, 2012-04-12 at 09:12 +0100, Tom Storey wrote:
> Also make sure to check flash: nvram: et al to make sure there arent
> "backup" copies of configs floating around.

When one erases flash/nvram in a Cisco router, or just deletes files off
it, is the data really gone? I have recovered allegedly deleted files
off all sorts of media, and even from formatted drives. I haven't tried
it off a Cisco switch or router.

It seems likely to me that long term storage devices in routers and
switches will retain most, and possibly all, of their data in a
recoverable or largely recoverable state unless explicit steps are taken
to overwrite it.

Maybe it would be a good idea to prepare a large file of random data and
write it to any long term storage devices at some point. Filling the
device with random data would probably leave a little structural info
untouched (directory entries and suchlike) but should obliterate most
actual data.

Since the flash memory in such devices is usually removable without much
difficulty, it might be possible to shred the data more conveniently
(and probably faster and more effectively) by putting it into a card
read/writer of some sort.

On the other hand, I could be wrong.

Regards, K.
Karl Auer (kauer at biplane.com.au)

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