http://php.net/manual/en/function.shell-exec.php
https://jhalon.github.io/vulnhub-mr-robot1/
http://f4l13n5n0w.github.io/blog/2016/08/29/vulnhub-pwnlab-init/
https://jhalon.github.io/vulnhub-stapler1/
https://www.vulnhub.com/entry/kioptrix-2014-5,62/#walkthrough
http://f4l13n5n0w.github.io/blog/2015/05/25/vulnhub-kioptrix-2014/
http://pentestmonkey.net/tools/web-shells/php-reverse-shell
https://www.exploit-db.com/exploits/38125/
https://blog.rapid7.com/2013/03/27/open-s3-buckets/
http://www.hackingarticles.in/spawn-tty-shell-using-msfvenom-one-liner-payload/
https://pentestlab.blog/tag/zone-transfer/
https://github.com/GoFetchAD/GoFetch
https://www.secplicity.org/2016/08/11/bloodhound-pen-test-tool-daily-security-byte/