As per Amazon's latest update, AWS will be be performing upgrades to infrastructure that should be completed at 1pm Eastern on January 4, 2018. This will take care of the underlying infrastructure issues. Amazon recommends an OS patch as well. While they have published the Amazon Linux patch, an Ubuntu patch is scheduled for 1/09. Critique^It will be implementing the patch immediately after publication.
The OS patch is a second-level precautionary measure while the root issue is resolved in the hardware update. Regardless, we will post an update as soon as the patch becomes available.