CTFs and other challenges

If you work in defensive security, it's still useful to participate in a regular CTF, but you can look for specific ones that involve forensics, reverse engineering, OSINT...

CTF Sites: a compilation of Capture The Flag (CTF) challenge platforms where users can test their hacking and cybersecurity skills.

BattleH4ck: a CTF platform offering challenges to enhance cybersecurity skills, particularly focused on offensive security.

The Black Side: offers various hacking challenges and competitions, focused on enhancing practical cybersecurity skills.

HackingHub: offers a collection of courses and "hubs" for practicing penetration testing and ethical hacking.

VulnMachines: provides labs designed for security professionals and enthusiasts to practice their exploitation skills.

OverTheWire Wargames: offers a variety of wargames that teach cybersecurity basics through hands-on challenges, with each game focusing on different aspects of hacking.

Root-Me: an online platform with a variety of hacking challenges.

picoCTF: gamifies learning hacking with capture-the-flag puzzles created by trusted computer security and privacy experts at Carnegie Mellon University.

PwnX: a virtual training ground for cybersecurity can help an organization or individual become more capable of withstanding and recovering from cyber threats, ultimately strengthening overall security posture and readiness.

247CTF: a security learning environment where hackers can test their abilities across a number of different Capture The Flag (CTF) challenge categories.

Pwnable.kr: non-commercial wargame site which provides various pwn challenges regarding system exploitation.

Unescape Room: this game will help you improve your Cross-Site Scripting (XSS) skills through challenges.

Ringzer0Team: tons of challenges designed to test and improve your hacking skills through hacking challenges.

KC7Cyber: transform into a digital detective, sift through data, and unravel mysteries. The new way of learning cybersecurity.

XSS Game: an interactive game designed to teach users about Cross-Site Scripting (XSS) vulnerabilities in a hands-on way.

Flaws.cloud: through a series of levels you'll learn about common mistakes and gotchas when using Amazon Web Services (AWS).

Capture the flag with Google: consists of a set of computer security puzzles (or challenges) involving reverse-engineering, memory corruption, cryptography, web technologies, and more.

CTF 101 from snyk: a virtual workshop helping you solve CTFs.