A lot many good things are being done in Docker. Jackhammer is another good example of this. The authors have gone ahead and put almost everything you would need for vulnerability assessment and vulnerability management, dockerized it, made it an all-in-one tool and put it up for us to use! A few other security related docker projects can be found here.
Kali Linux really needs no introduction today. It is the de-facto open source, Debian-based operating system for penetration testing, vulnerability assessments, digital forensics and wireless assessments. It is one of those operating systems that I see being actively developed and has a huge and helpful community. This post talks about the improvements and new tool additions in the latest open source Kali Linux 2017.1 Rolling release.
All of us know that a typical penetration testing engagement begins with reconnaissance (run nmap, etc.), testing for services & their default passwords then moving onto launching common exploits (Metasploit, etc.), getting access and then lateral movement. This is okay on small networks, but tends to be slow on large networks. Fortunately, we have APT2 to help us!