What are rootkit attacks?

Rootkits are associated with malicious software that provides root-level remote access to a computer or a computer network while hiding itself and its actions from the user and the operating system.

Note: The name "rootkit" derives from "root," the most privileged account admin in Unix and Linux OS. Applications that allow unauthorized root-level access to the device are known as the "kit."

How rootkits operate

Rootkits cannot replicate themselves. Therefore, they depend on hidden means to infect the system. They are activated by an attacker when a user allows permission for the rootkit installation. They propagate in the following ways:

• Phishing email campaigns. 

• Malicious executable files. 

• Fraudulently designed PDF or Microsoft Word documents. 

• Infected shared folders.

• Rootkit- infected software on infected sites.

What are the consequences of a rootkit attack?

Rootkits can allow an attacker to carry malicious routines on a system, and therefore, it can result in:

• Increased vulnerability of DDoS attacks. 

• Stealing sensitive data. 

• Deactivation of security software.

• Malware infection. 

• Removal of operating system's directories, registry keys, and files.

What are some examples of rootkit attacks?

The following is a list of well-known rootkit attacks that have been conducted:

• Stuxnet

• ZeroAccess

• Necurs

• Dridex

• Zeus

• Flame

• NT Rootkit

What are the types of rootkit attacks?

• Kernel rootkits: They function at the level of the OS. They can add, delete, or replace OS code.

• Hardware and firmware rootkits: They work by accessing a system's BIOS or hard drives (routers, memory chips, network cards, and so on). 

• Virtualized rootkits: They use virtual machines to control the OS. They create a virtual machine before the OS is loaded. Therefore, they operate at a higher level than the OS. 

• Bootkits: A bootkitA bootloader rootkit. replaces the original bootloaderA bootloader is a mechanism responsible for loading the Operating System on a computer. with an infected one. Therefore, bootkits become active before the OS is fully loaded.

• Memory rootkits: They hide in the computer's RAM—these work by using the resources of a computer to conduct malicious activity.

• Application rootkits: They replace files with infected files on the system. They usually operate by infecting standard programs. Therefore, they can be detected using anti-virus software. 

How to detect rootkit attacks

Rootkits are hard to detect as the OS of an infected system cannot be trusted. Rootkits can be detected through the following means:

• Memory dump analysis: It refers to the analysis of the volatile data in a computer's memory dump.

• Behavioral analysis: Blue screen, slow device performance, settings change without permission, unusual web browser behavior, anti-malware deactivation. 

• Signature scanning: Rootkit scans look for signatures left by hackers; this is done by turning off the infected system while a clean system conducts the scan.

How to defend against a rootkit attack

Rootkit attacks can be prevented by following anti-phishing measures, regularly updating OS software, and so on. However, if a rootkit attack has been detected, then the following steps can be followed to remove it: 

• Step 1: Back up vital data.

• Step 2: Boot up in safe mode.

• Step 3: Freeze the remaining malware and wipe the device.

• Step 4: Use specialized tools for rootkit removal.

• Step 5: Update the operating system.

• Step 6: If the issue persists, reinstall the operating system and get the hardware of the device replaced.