• https://captf.com/practice-ctf/
• https://unaalmes.hispasec.com/login
• https://365.csaw.io/
• https://defcon2018.ctfd.io/
• https://ctf.hackucf.org/challenges
• http://ctf.infosecinstitute.com/index.php
• https://junior.stillhackinganyway.nl/home#challenge-information
• https://challenges.re
• https://angstromctf.com
• https://3206.innotecsystem.com/home
• https://hack.me
• http://www.cipher-ctf.org/CaptureTheFlag.php
• https://www.cybergamesuk.com/code-crackers
• https://atenea.ccn-cert.cni.es/home
• https://www.hackthebox.eu/
• http://ctfs.me/
• https://ctf365.com/
• https://overthewire.org/wargames
• https://www.hacking-lab.com/
• https://www.picoctf.com
• https://ctftime.org/
• https://www.pentestit.ru/
• https://shellterlabs.com/en/
• https://ringzer0team.com/
• https://challenges.ka0labs.org
• https://www.sans.org/netwars/continuous/
• https://www.sans.org/netwars/cybercity
• https://www.vulnhub.com/
• https://exploit-exercises.com
• https://w3challs.com/
• http://smashthestack.org/wargames.html
• https://www.hackthissite.org/
• https://www.pentesterlab.com/exercises/
• https://www.root-me.org/
• https://www.enigmagroup.org/
• https://www.hackthis.co.uk/levels/
• http://www.kioptrix.com/blog/test-page/
• http://bright-shadows.net/
• https://microcorruption.com/login
• http://www.dvwa.co.uk/
• https://www.owasp.org/index.php/Category:OWASP_WebGoat_Project
• https://sourceforge.net/projects/metasploitable/
• https://bitcoinchallenge.codes
• https://backdoor.sdslabs.co
• http://io.netgarage.org
• https://ctf.hitcon.org
• http://hackthis.co.uk
• https://ctf.secadmin.es
• https://uni.hctf.fun/pages/home
• https://ctf-classic.ihacklabs.com/
• http://ctf.hackmadrid.org/home
• https://ctf.honeycon.eu