Pentesting
https://www.virtualhackinglabs.com/arrow-up-right
https://www.hackthebox.eu/arrow-up-right
If you work through retired machines, https://0xdf.gitlab.io/arrow-up-right has some of the best writeups.
https://lab.pentestit.ru/arrow-up-right
https://www.vulnhub.com/arrow-up-right
https://www.zeropointsecurity.co.uk/rastalabsarrow-up-right
an immersive Windows Active Directory environment, designed to be attacked as a means of learning and honing your engagement skills
https://www.wizlynxgroup.com/pwntilldawn-ctf/arrow-up-right
Wargames / CTFs
http://www.pwnable.kr/play.php#arrow-up-right
OverTheWire.org
2018game.picoctf.com
247ctf.com
defendtheweb.net
Training
https://seedsecuritylabs.org/labs.htmlarrow-up-right
http://exploit.education/arrow-up-right
SEED Labs
Last updated 5 years ago