Re: Easy come, easy go?
That most likely these installations were commissioned band wagon jumpers who were told that big data would revolutionise their business metrics; employed any freelancer that had mongoDB on their c.v. threw all their data at an installation on a cheap AWS instance and then watched as nothing happened.
This is a scenario where quite possibly in the course of an experiment with "big data", a company may not know what information has been leaked, lost or even looked at the legacy instance in months and hence the general inaction. That the patches for mongoDB have been out for just over a year, that the version most affected is 2.4.9 (when mongo is now at 3.4) all indicate temporary contractors.*
* information about the hack from the original articles, theory derived from cleaning up this kind of thing multiple times.