Does Ubuntu need anti virus. Let me share our recent experience, we are coming to the end of of redeveloping or site on a new Linux server, running Ubuntu, ROR & Mongo. The server is to deploy our multiple directories which will accept Video/Audio and Text data. The server is still in dev mode and NOT public facing.
But we have had 2 instances of malware being installed, for spam distribution, this was picked up by the ISP as unusual traffic for a server in Dev mode. developing. This server does not have any inbound traffic apart from the developers (who) naturally are denying they are the source. But who else can it be as they are the only ones with access.
My point is, that once we have deployed to the live server users of our service will be able to create links YouTube etc, upload images, video, audio files, data and Pdf's.
Fortunately these 2 attacks have occurred during dev phase, had they occurred once the site is released it would have killed our service as the server would have had to be taken down.
So, whilst I understand the majority sentiment that Linux/Ubuntu is safe, I am afraid, from our experience it is not. Therefore we are having to investigate what security solutions are available.