On 11/18/2015 12:57 PM, Day, David wrote:

-----Original Message-----
From: Adrian Klaver [mailto:adrian.kla...@aklaver.com]
Sent: Wednesday, November 18, 2015 3:47 PM
To: Day, David; pgsql-general@postgresql.org
Subject: Re: [GENERAL] postgres zeroization of dead tuples ? i.e scrubbing dead 
tuples with sensitive data.

On 11/18/2015 11:45 AM, Day, David wrote:
Hi,

One of my co-workers came out of a NIST cyber-security type meeting
today and asked me to delve into postgres and zeroization.

I am casually aware of mvcc issues and vacuuming

I believe the   concern,  based on my current understanding  of postgres
inner workings,  is  that when a dead tuple is reclaimed by vacuuming:
   Is that reclaimed space initialized in some fashion that would
shred any sensitive data that was formerly there to any  inspection by
the subsequent owner of  that disk page ? ( zeroization )

Got to thinking, are you talking about a physical machine or a VM/container on 
shared hosting? If the latter then it is a more generic problem of detritus 
left behind between creations of virtual instances or cross talk on shared 
storage.


Not sure that is the exact question to ask but hopefully you get a
feel for the requirement is  not to  leave any sensitive data laying
about for

recovery by a hacker,  or at least minimize the places it could be
obtained without actually being able to log into postgres or having
raw disk access privileges.

Thanks for any comments/instruction/links on the matter.

Regards

Dave Day



--
Adrian Klaver
adrian.kla...@aklaver.com

In some instances this would be a vm instance on a hosted machine in other 
cases a actual physical machine.

Thank you all for the feedback.


All good points.  I am not sure what the manner of attack/hack is until I get 
some further feedback out of the meeting participants.  I suspect it would be 
to the blocks pages released by postgres following a vacuum full.
How you determine what those pages blocks were I am not sure but suspect there 
is probably a way.
When I get some more detail on the standard and exact requirement I will repost 
with that info.

Yes, a detailed problem description would be helpful.



Again thanks



Dave Day






--
Adrian Klaver
adrian.kla...@aklaver.com


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