This is Kali Linux's ISO images repository: http://cdimage.kali.org/

Kali Linux is an open source security auditing and penetration testing Linux
distribution: http://www.kali.org

Download Kali Linux ONLY from official mirrors!
http://docs.kali.org/downoading/download-official-kali-linux-images

Grab the latest images from the "kali-latest" directory.

Kali Linux is a project by Offensive Security - http://www.offensive-security.com