COMMAND
MS Office 98 (Word98 vulnerability described)
SYSTEMS AFFECTED
MacOS With MS Office 98
PROBLEM
Mike Morton found following:
1. Open a few documents, work on your Macintosh for a while.
2. Open word 98 and compose a message, then save it to your
dirve.
3. Attach the document to an email, and send it.
4. open the resulting document from the email when you
receive it in BBEdit.
The file can be read plain text with all sorts of juicy
information like passwords, URLS, document locations, etc, all
from the origionating computer. We have been able to successfully
gleam passwords and logins from the file, IN PLAIN TEXT. It
contains information that is MONTHS old from the orginating
computer. This was tested only on the Macintosh version of Word
98, and the emails were sent via Eudora. Btw, if you open the
saved document on your harddrive - you get the same results!
This is reproducable from Word 2.0 version. While the likelihood
of revealing sensitive information is low, if this file were then
sent to another user, it could possibly expose data from a
previously deleted file on the sender's system.
The problem is caused by the way Office 98 allocates space on a
disk for local file storage. The Mac OS -- like many other OS'
file systems -- does not erase files when you delete them, it
simply removes a reference to them in the disk's catalog, and
marks the space they occupied as "free." Office 98 does not clear
the disk space when the Mac OS allocates it during a File Save
operation. Instead, Office 98 simply writes the file contents to
the allocated disk space, overwriting any random data that
physically existed on the disk. Since the Mac OS allocates the
disk space in set chunks, called clusters, the small amount of
unused space at the end of the file's last cluster may contain
random data from previously-deleted files. The data cannot be
viewed when opened as a native Office file. However, an ASCII
text editor can be used to view the extraneous data.
SOLUTION
Microsoft recommends that customers using Office 98 for the
Macintosh install the available Office 98 update, which can be
downloaded from the Office 98 for the Macintosh web site at:
http://www.microsoft.com/macoffice
Previous versions of Office for the Macintosh are not affected.
Customers who cannot apply the hot fix can use the following
workarounds to temporarily address this issue:
- This problem can be eliminated by using a third party disk
utility for the Mac OS that completely erase files when they are
deleted.
- Users can save files to freshly formatted floppy disks to ensure
that there is no unwanted data included with the file.
- This issue only affects files that are saved to a local
Macintosh volume. By performing a "Save As..." operation from
Office 98 and saving the file to network volume, such a to a
Windows NT Server running Services for Macintosh, any random
data at the end of the file will be removed.