A rootkit is a type of malicious software (but not always) which gives the attackers privileged access to a computer and is activated before the operating system boots up. Rookits are created to conceal the existence of other programs or processes from being spotted by traditional detection methods. For example, rootkit malware is capable of covering up the fact that a PC has been compromised. By gaining administrator rights on the affected PC (through exploits or social engineering), attackers can maintain the infection for a long time and are notoriously difficult to remove.