During the time I have collected various resources that help me practicing CTF skills, divided per each category. Some of the exercises found in these sites are solved in the Security Exercises section. Web Web https://github.com/cure53/XSSChallengeWiki/wiki The repo offer a good collection of XSS related challenges. Although last update is from 2014, it stores a lot of references to other websites with related solution. Web https://github.com/swisskyrepo/PayloadsAllTheThings/tree/master/XSS%20Injection The repo offers examples of XSS in different scenarios. Web https://github.com/s0md3v/AwesomeXSS The repo has good reference material to understand XSS and some references to existing challenges. Reverse Reverse https://challenges.re It offers many reverse challenges dividing them in categories as OS, architecture and levels. It does not provide solutions. Crypto Crypto https://cryptopals.com Very good reference to implementing algorithms. It goes from zero to hero. It helps you to build famous crypto attacks like breaking an MD4 and SHA-1 keyed MAC using length extension. It doesn't offer challenges like broken algorithms to brake or CTF like challenges. Exploit Exploit https://github.com/shellphish/how2heap It is a colletion curated from the Shellphish team from UCSB. Exploit http://pwnable.kr/play.php Very famous and well curated site that offers a good variety of challenges. There are a lot of online write ups if you are stuck. Exploit https://old.liveoverflow.com/binary_hacking/protostar/stack0.html A very good resource for stack-based and heap-based buffer overflow. The challenges were thought for 32 bit architecture and the the online videos as well but with provided the source code you can compile it in 64 bit as well. Exploit https://ropemporium.com The site offers many resources to guide you through the construction of ROP. It offers both 64 and 32 bit examples for the same challenge. Network Forensics -- Miscellaneous Write-up https://github.com/ctfs A collection of write ups from previous CTFs divided per year. CTFs Reference https://ctftime.org This is the place where you want to be to get news and upcoming events always up to date.