I worked a Maersk for a couple of years. This happened once before, we came in and all Maersk's machines were randomly shutting down.

I heard later a rumour that the reason the AV didn't pick it up was it was a 0-day (stuxnet derived before that was known) and it was literally targeting the SCADA systems on boats.. but that's also the plot of Hackers, so take that with a pinch of salt.

Anyway being the build/devops/tooling person on a project i burned 40 dvd's with eclipse and ubuntu and handed to them to the devs and they booted into Ubuntu and kept developing.

All was going fine until i got a telling off from the Corporate IT security team complaining that our unauthorised Ubuntu machines weren't running AV and so could be introducing viruses into the network.

Total facepalm.