Site URL Cost
HackTheBox https://www.hackthebox.eu/ Free
PicoCTF https://picoctf.com/ Free
VulnHub https://www.vulnhub.com/ Free
UnderTheWire https://underthewire.tech/ Free
OverTheWire http://overthewire.org/wargames/ Free
CTF365 https://ctf365.com/  
Hacking-Lab https://www.hacking-lab.com/index.html  
pwnable.kr http://pwnable.kr/  
IO http://io.netgarage.org/  
SmashTheStack http://smashthestack.org/  
Microcorruption https://microcorruption.com/login  
reversing.kr http://reversing.kr/index.php  
Hack This Site https://www.hackthissite.org/  
W3Challs https://w3challs.com/  
pwn0 https://pwn0.com/  
Exploit Exercises https://exploit-exercises.com/  
RingZer0 Team Online CTF https://ringzer0team.com/  
Hellbound Hackers https://www.hellboundhackers.org/  
Try2Hack http://www.try2hack.nl/  
Hack.me https://hack.me/  
HackThis!! https://www.hackthis.co.uk/  
Enigma Group https://www.enigmagroup.org/  
Google Gruyere https://google-gruyere.appspot.com/  
Game of Hacks http://www.gameofhacks.com/  
Root Me https://www.root-me.org/  
CTFtime https://ctftime.org/  
SANS Holiday Hack Challenge https://holidayhackchallenge.com  
PentesterLabs https://pentesterlab.com/ Paid