https://www.pentesterlab.com/exercises/ - Online and Offline VMs (free + paid subscriptions)
https://www.hackthebox.eu/ - Pentest Lab (free + paid subscriptions)
https://www.vulnhub.com/ - Vulnerable offline VM challenges (lots of great content here)
https://exploit-exercises.com/ - Vulnerable offline VM challenges
https://w3challs.com/ - Online challenges in multiple categories
http://smashthestack.org/wargames.html - Online challenges
https://www.hackthissite.org/ - Online challenges in multiple categories
https://hack.me/ - Similar to vulnhub
https://www.root-me.org/ - Online challenges & virtual environments
https://www.enigmagroup.org/ - OWASP top 10 based challenges
https://www.hackthis.co.uk/levels/ Over 50 challenges with multiple categories
http://www.kioptrix.com/blog/test-page/ - Offline VM challenges
http://bright-shadows.net/ Over 300 challenges with multiple categories
https://microcorruption.com/login - Embedded Security CTF
http://www.dvwa.co.uk/ - Damn Vulnerable Web App (DVWA)
https://www.owasp.org/index.php/Category:OWASP_WebGoat_Project - Web Goat (OWASP)
https://sourceforge.net/projects/metasploitable/ - Metasploitable
https://overthewire.org/wargames/ - Step-by-Step Pentest Lab
https://www.hacking-lab.com/ - Pentest Lab (free + paid subscriptions)
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