Note: you should check the following presentation instead.

http://www.slideshare.net/jpetazzo/docker-linux-containers-lxc-and-security



It contains in-depth, up-to-date material about the topic.



Original description follows.



It is often told that Linux Containers (LXC) are not secure. This was definitely true 3 years ago, but they got much better. Here is a quick overview of current challenges, as well as ways to improve container security when needed.