Thanks to Roy’s tenacity and constant vigilance, I have learned how it now appears the MS Office binary format that is wrapped in XML and is now known as IS 29500 (OOXML), an ISO Standard Office Document Specification (ROTFL), is giving hackers everywhere a field day.
It is now official and also confirmed that OOXML files are not just insecure but there are also persistent attacks against new flaws (without any security patches being available, i.e. zero-day).
There are some good links and sources to this article so recommended reading for anyone who is considering using Office 2007 or receives an OOXML document (the ones ending in x, e.g docx, pptx and xlsx). IMHO your automatic response should be to return it directly to the sender, do not attempt to open it, and ask for them to send it to you in an open format such... read more