Definition
A rootkit is a type of malicious software designed to gain unauthorized access to a computer system and conceal its presence. It operates at a deep level within the operating system, often modifying core system functions to hide its files, processes, and network connections from detection. Rootkits are particularly dangerous because they allow attackers to maintain persistent control over a compromised system, making them difficult to remove. For instance, a bootkit, a type of rootkit, can infect the system's boot loader, executing before the operating system even starts. Unlike a virus or worm that actively spreads, a rootkit's primary goal is stealth and persistence, enabling other malware to operate undetected. Understanding rootkits is crucial for cybersecurity professionals and is a key topic on certifications like CompTIA Security+ and CISSP.