[1] Software Exploitation :
- http://smashthestack.org/
- Microsoft BlueHat Challenge
[2] Embedded Exploitation : https://microcorruption.com/
[3] RCE :
- http://www.crackmes.de/
[4] Crypto :
- Matasano Crypto Challenges : web.archive.org/web/20140213141638/http://www.matasano.com/articles/crypto-challenges/
[5] Web Exploitation : https://pentesterlab.com/exercises/
[6] Others :
- http://www.wechall.net/
[7] Forensics :
- http://old.honeynet.org/challenge/
[8] Linux kernel programming : http://eudyptula-challenge.org/