secure data export

[Orna Agmon Ben-Yehuda]

Hello all security experts,

I would like to export data from a machine on a business's internal network
on a safe media, such that only the files I want exported are on the media.
Specifically, I consider the possibility that the machine may already be
infected by a malware which adds business-sensitive data to all outgoing
media, and would like to defend against such a theoretical malware. The
question may be limited to text files.

Things already considered:
*The media is a CD, which will be written and then finalized. No USB
devices.
*An artificial file will be added to the data file, to fill the media as
much as possible. This, however, leaves a part of the disk capacity unused -
the part used for the structure table (what used to be FAT), which is a
place where additional data can hide.
*The CD will be read in two different machines, with two different operating
systems. One of the systems will be a bootable linux disk, to preserve its
(hopefully) initial not-infected status. The listing of files will be
performed including hidden files (ls -la in Linux). The person who wrote the
files will read them, to verify they contain the correct information.

Questions:
What else should I do?
What about a malware compressing the data, using the extra space for
additional data?
If I compress the data to avoid further compression, how can the person
verify it contains exactly what it should?
What can I not defend against?
Are such malware as I imagine known? For Linux? Windows?

Thanks for considering the problem,
-- 
Orna Agmon Ben-Yehuda.
http://ladypine.org
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