Rootkit
Adversaries may use rootkits to hide the presence of programs, files, network connections, services, drivers, and other system components. Rootkits are programs that hide the existence of malware by intercepting/hooking and modifying operating system API calls that supply system information. (Citation: Symantec Windows Rootkits) 

Rootkits or rootkit enabling functionality may reside at the user or kernel level in the operating system or lower, to include a hypervisor, Master Boot Record, or [System Firmware](https://attack.mitre.org/techniques/T1542/001). (Citation: Wikipedia Rootkit) Rootkits have been seen for Windows, Linux, and Mac OS X systems. (Citation: CrowdStrike Linux Rootkit) (Citation: BlackHat Mac OSX Rootkit)
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1014  external_id: T1014     source_name: CrowdStrike Linux Rootkit  description: Kurtz, G. (2012, November 19). HTTP iframe Injecting Linux Rootkit. Retrieved December 21, 2017.  url: https://www.crowdstrike.com/blog/http-iframe-injecting-linux-rootkit/     source_name: BlackHat Mac OSX Rootkit  description: Pan, M., Tsai, S. (2014). You can’t see me: A Mac OS X Rootkit uses the tricks you haven't known yet. Retrieved December 21, 2017.  url: http://www.blackhat.com/docs/asia-14/materials/Tsai/WP-Asia-14-Tsai-You-Cant-See-Me-A-Mac-OS-X-Rootkit-Uses-The-Tricks-You-Havent-Known-Yet.pdf     source_name: Symantec Windows Rootkits  description: Symantec. (n.d.). Windows Rootkit Overview. Retrieved December 21, 2017.  url: https://www.symantec.com/avcenter/reference/windows.rootkit.overview.pdf     source_name: Wikipedia Rootkit  description: Wikipedia. (2016, June 1). Rootkit. Retrieved June 2, 2016.  url: https://en.wikipedia.org/wiki/Rootkit     