Imagine my horror to read that Xerox Copiers, specifically the Xerox Workcentre 7535 and 7556, using Jbig2, an image compression standard, are unilaterally changing numbers within documents. The BBC report is here. In a specific example, dimensions in a plan which was copied were changed from 21.11m to 14.13m.
To my naturally devious mind this presents an opportunity to wage economic warfare on a rival company or on an adversary. Imagine I, as an attacker, know that you have networked copiers or perhaps scanners. What would prevent me from replacing imagery compression programs in your system with altered programs which changed figures by a pre-calculated amount, perhaps only 1.5%? What if I were to put a command into your system which only performs this on irregularly sequenced documents, every 7th, then every 3rd for a little while, then every 19th. This is just enough to make any and all documents originating from your company of doubtful quality, your reputation would suffer and without definite proof, your sales would plummet. Even with proof, your systems are no longer considered secure and your reputation could be ruined. Imagine if I could do this to your entire system, altering a great many documents that you sent out of your network?
This would be yet another form of an advanced persistent threat. How secure are your networks? Just because we haven’t seen it doesn’t mean it won’t be done. We now have a proof of concept. Be paranoid, be very paranoid.