- https://ctftime.org/ctfs
- https://www.hackthebox.eu/ – Playground for red-team skills
- https://hack.me/ – Similar to HTB but not as in depth
- https://cryptopals.com/ – Challenges to practice reversing/breaking crypto
- https://ctf101.org/ – Great resource for beginning with CTFs
- https://github.com/apsdehal/awesome-ctf – AWESOME list to reference
- https://github.com/vitalysim/Awesome-Hacking-Resources – Awesome list of resources
- https://www.tracelabs.org/ – Crowdsourced OSINT For Missing Persons
- https://www.malwaretech.com/challenges – Malware reversing
- https://www.hacker101.com/ – Site for learning about web security
- https://hshrzd.wordpress.com/how-to-start/ – Links for learning reverse engineering
Casey Trader 