To use John the Ripper on Office 2007/2010 encrypted files, first build
the included office2john program with "make office2john" in the src/
directory.  Please note that it has extra prerequisites compared to John
itself, which is why it is not being built by default.  Thus, you will
need to install additional "development" packages first.

Follow steps below to successfully build and run office2john program.

1. Install libgsf library

   a) On Ubuntu, do

   $ sudo apt-get install libgsf-1-dev

   b) On CentOS / RHEL / Fedora, do

   $ sudo yum install libgsf-devel

   c) On Arch Linux, do

   $ sudo pacman -S libgsf

2. Install libxml2 library

   a) On Ubuntu, do

   $ sudo apt-get install libxml2-dev

   b) On CentOS / RHEL / Fedora, do

   $ sudo yum install libxml2-devel

   c) On Arch Linux, do

   $ sudo pacman -S libxml2

3. Run "make office2john" in the src/ directory

4. Run office2john on Office 2007 / 2010 files.

5. Run john on the output of office2john.