Final answer:
Rootkits can modify operating system-level files, kernel modules, and even the boot loader, allowing them to gain privileged access and hide their presence on a computer system. They are sophisticated and tough to detect, thus requiring strong security measures and cautious software management.
Step-by-step explanation:
Rootkits are a type of malicious software that can give attackers unauthorized access to a computer system without being detected. These can modify various levels of files, including those at the operating system level, and can intercept and alter standard system functions to hide their presence. Rootkits can manipulate system files and kernel modules, enabling ongoing privileged access to the infected machine.
They can also target the boot loader, which is the part of the operating system responsible for starting the computer, and the system firmware, which is a low-level code that initiates hardware during the bootup process. Due to the sophisticated nature of rootkits, they are capable of hiding processes, files, network connections, and system data, making them difficult to detect and remove with standard antivirus software. Preventing rootkit infections requires up-to-date security software and cautious practices regarding software installation and system access.