Practice CTF List / Permanant CTF List

Here's a list of some CTF practice sites and tools or CTFs that are long-running. Thanks, RSnake for starting the original that this is based on. If you have any corrections or suggestions, feel free to email ctf at the domain psifertex with a dot com tld.

Live Online Games

Recommended

Whether they're being updated, contain high quality challenges, or just have a lot of depth, these are probably where you want to spend the most time.

http://pwnable.tw/ (a newer set of high quality pwnable challenges)

http://pwnable.kr/ (one of the more popular recent wargamming sets of challenges)

https://picoctf.com/ (Designed for high school students while the event is usually new every year, it's left online and has a great difficulty progression)

https://microcorruption.com/login (one of the best interfaces, a good difficulty curve and introduction to low-level reverse engineering, specifically on an MSP430)

http://ctflearn.com/ (a new CTF based learning platform with user-contributed challenges)

https://cherryblog.in/

http://reversing.kr/

http://hax.tor.hu/

https://w3challs.com/

https://pwn0.com/

https://io.netgarage.org/

http://ringzer0team.com/

http://www.hellboundhackers.org/

http://www.overthewire.org/wargames/

http://counterhack.net/Counter_Hack/Challenges.html

http://www.hackthissite.org/

http://vulnhub.com/

http://ctf.komodosec.com

Others

Meta

http://www.wechall.net/sites.php (excellent list of challenge sites)

http://ctf.forgottensec.com/wiki/ (good CTF wiki, though focused on CCDC)

http://repo.shell-storm.org/CTF/ (great archive of CTFs)

Webapp Specific

Forensics Specific

Recruiting

Commercial/Freemium/Paid Training

https://www.root-me.org/ (well done set of challenges free for public use with optional paid commercial versions)

https://avatao.com (paid commercial training platform from a CTF team, though with a strong focus on secure app development)

http://heorot.net/

Downloadable Offline Games

Virtual Machines

Inactive or Gone

Just around for historical sake, or on the off-chance they come back.