After a new outcry over a flaw that could allow a user to “bug” a Word
document being sent to another user for review, Microsoft
says it is working
on a fix.
In a statement issued Thursday, the Redmond, Wash.-based software giant said
it would definitely repair the problem, but was unclear whether it would fix
the flaw only for owners of the most recent versions of the software.
While all versions of Word are susceptible to the flaw, the problem is most
severe in Word 97. If Microsoft proceeds with a fix only for newer versions
of the software, it could leave millions of users of Word 97 hanging in
The attack, which was recently rediscovered in a report
by Qualcom employee Alex Gantman, sends the victim a “bugged” document,
which embeds the INCLUDETEXT field into the document. The field results in
inclusion of a specified file into the current document.
The document is usually accompanied with a request that the document be
revised and returned to the sender.
The attacker would likely make hide the INCLUDETEXT field by using hidden
text, small white font, or other tricks. Alternatively, the attacker could
embed the INCLUDETEXT field within a dummy IF field that always returns an
empty string. In this case, the only way to detect the included file is if
to browse through field codes.
When the document is changed and sent back, the file the attacker wants to
steal is attached.
According to the Associated Press, Microsoft says an attacker would
have to know the exact file name to be stolen and its location. But many
critical files an address book or saved e-mails, for example are usually
in obvious or predictable places on every Microsoft Windows computer.
Word 97, still widely-used in both the home and small offices, is most
susceptible to the attack. According to the AP, Microsoft said it is its
policy to no longer repair Word 97, but said the company is still exploring
According to Gantman’s report, the only countermeasure to be taken, if you
must send and edit documents, is to manually go through the fields in the
document to look for code or write a scanner to search the fields.