full-disclosure - Windows covert channel

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From: WEaton at coj.net (Wally Eaton)
Subject: Windows covert channel

James,
You may be thinking of "Streams" in Windows files. Data can be hidden in secondary files on NTFS partitions. I believe it was developed to be compatible with Apple/ MAC systems. In any case the following is an example:

Run CMD
On a NTFS partition

D:\> echo Hello > FrontFile
D:\> type FrontFile
Hello

D:\> echo Good Day >> FrontFile
D:\> type FrontFile
Hello
Good Day

D:\> echo Secret Info > FrontFile:BackFile
D:\> type FrontFile
Hello
Good Day

D:\> more < FrontFile:BackFile
Secret Info

Now add data to the FrontFile only

D:\> echo Good Evening >> FrontFile
D:\> type FrontFile
Hello
Good Day
Good evening

Now add data to the BackFile only

D:\> echo More Secret Data >>FrontFile:BackFile
D:\> more < FrontFile:BackFile
Secret Info
More Secret Data

You will notice if you enter a DIR command that only the FrontFile will be displayed. Furthermore, the size of the file will reflect only the content of the FrontFile.
Have a great day.
Wally