From Bruce Berger, Executive Director of Maine Water Utilities Association:
I just received a call from a utility here in Maine. There have been several security breaches within Maine for two confirmed utilities that are being held hostage. There may possibly be a third.
In this case as was other cases across the US, the vulnerable point is Windows 7. If any utilities have a windows 7 based system they need to upgrade ASAP. Secondarily any and all PLC’s are also vulnerable and need to have security measures implemented ASAP.