XLS XOR password cracker 1.2
Copyright (C) 2003-7  Nick Lamb <njl+xlcrack@filter.tlrmx.org>


This updates the previous version to work better with non-ASCII characters
including correctly guessing the non-ASCII passwords I was able to try.

Please report any bugs, especially bugs where a password was partially
recovered by this tool, or where an XLS crashed the software (a corrupted
XLS should cause an error to be reported and obviously won't find the
password but it shouldn't crash)

What does the tool do?
----------------------

This program recovers lost passwords for XLS files, such as those saved
by Excel 95. In order to do this it implements a simple XOR encryption
algorithm common to several Microsoft Office applications.

What does this tool NOT do?
---------------------------

Microsoft added better cryptography to Excel 97 and again to Excel XP.
The improved encryption prevents instant password recovery, but it was
not available in some countries, and is disabled when saving files
for an earlier version of Excel so you may still have some luck. The
tool will immediately detect and report the newer encryption, so that
you know more powerful software (and a lot more time) is needed.

How to use
----------

Simply apply the tool to any XLS file, and the lost password will be
recovered if possible. e.g.

xlcrack lostpassword.xls
lostpassword.xls: password is 'MyLittleDog'

You can suggest more than one XLS file, but at the moment the password
will be recovered for each file individually. If you have a lot of
files with the same password, maybe a future verison of xlcrack can
use that to get better results.

Foreign characters
------------------

Excel doesn't seem to use Unicode for passwords, at least not in the
versions I was able to test. This program assumes that any non-ASCII
characters are from Windows codepage 1252, used in Western European
versions of Windows. On modern systems (technically, when your locale
charmap is UTF-8) this software can display the password correctly,
on other systems such characters are displayed as an asterisk, '*'.

No password? 
------------

XLS files are sometimes encrypted without using a real password, in this
situation the key is generated as though the password VelvetSweatshop had
been used (you can find more information by searching for VelvetSweatshop on
the web, e.g. with Google)

xlcrack reports that the file "has no password" in this case.

Some 3rd party software will ask for a password when opening this type
of XLS file, or it may declare that the file is "password protected"
although the person who created the spreadsheet did not set a password.
In this case you probably need to upgrade to a version without this
limitation.

