Reptile is a LKM rootkit for evil purposes. If you are searching stuff only for study purposes, see the demonstration codes. Features:

Give root to unprivileged users
Hide files and directories
Hide files contents
Hide processes
Hide himself
Boot persistence
Heaven’s door – A ICMP/UDP port-knocking backdoor
Client to knock on heaven’s door 😀

http://www.kitploit.com/2017/10/reptile-lkm-linux-rootkit.html

https://github.com/f0rb1dd3n/Reptile