I am currently working on a project that hopes to more fully digitise inter-organisational trading and workflows (corda.net).

There are numerous problems to solve to make this kind of attack unviable. The key thing to understand is that whilst the software industry has done a good job of automating and improving intra-business work, through things like office and enterprise software, it's had relatively little impact on inter-business work, which is still mostly paper based. Even when workflows are theoretically digitised, it's often simply by sending scans of paper forms or Word/PDF files via email. There are exceptions in the travel and financial industries (with SABRE and SWIFT respectively), but those are relatively restricted networks - for instance I doubt Google or its suppliers are directly connected to SWIFT.

There's some low hanging fruit. Email has DKIM and DMARC. Deploying these widely would make the From header reliable, at least assuming unhacked machines. It isn't intuitive that the From header can't be trusted and office workers typically assume that it is ... after all, it's normally correct and why would something as critical as email allow anyone to impersonate anyone else? But by default, it does.

Unfortunately DMARC is a fairly recent standard and the email space is quite stagnant, so many organisations don't use it, making email-based phishing trivial. It also hits the problem that lots of organisations have developed insecure mail practices over time in which impersonation is common, like marketing firms that send email on another organisations behalf, so deploying DMARC isn't as simple as just switching it on. It can often take months to track down and fix all the mail being sent with a "From: someone@foo.org" header but which actually wasn't sent by foo.org servers. That means it's a project that needs a budget, and that in turn means it often doesn't get proposed or worked on. Especially because the victims of email phishing are typically other companies, not the company being impersonated.

But because DKIM and DMARC are fundamentally based on digital signatures, and because the workflows being attacked are so often email based, setting up DKIM/DMARC is one of the best practical ways to secure modern business.

Now ... longer term, email with Word documents attached is not a solid base on which to link businesses together, DKIM/DMARC or not. It's hard to automate. It's very susceptible to human error. It suffers strange limitations, like tiny attachment sizes. Organisations often mutilate it, like with mandatory headers/footer legal disclaimers that are larger than the messages itself, or with vacation responders that don't understand mailing lists. And as nobody really coordinates or is responsible for the email network, nobody is incentivised to improve it. When improvements happen, they happen slowly and mostly because Google or Yahoo employees made it happen through sheer force of will.

Corda is an open source project that is trying to build a new inter-business network, focused (for now) on finance. So things like invoicing and bill paying is very much in scope. It uses digital signatures and encryption pervasively from the start. It takes a lot of inspiration from Bitcoin and the block chain space, although it does not use chains of blocks or proof of work itself. Some of what it does is focused on building a kind of shared global database, albeit one with rather different properties to a normal database, but part of what it does is make it easy to build structured workflows between firms using straight-line blocking code that resembles a written English description of the process. So there's plans to support human interaction in these workflows, but ultimately, the goal is to try and get them off email and paper based processes and onto something more secure and more structured. There's a paper here that goes into some of the details:

https://docs.corda.net/_static/corda-technical-whitepaper.pd...