What is a rootkit?

7th October 2025

Hard to detect and potentially very dangerous, are you prepared to counteract this type of malware?

Malware based attacks, particularly those coming from phishing emails, are becoming more common and diverse. Often, it might be impossible to know if your systems have been impacted, until it is too late.

Rootkits are one type of this malicious software. Designed to give unauthorised users privileged access to a computer system, while remaining undetected. “Root,” means the highest level of access in Unix/Linux systems, while “kit,” refers to the software tools used to gain and maintain that access.

These rootkits can be installed by:

·         Phishing attacks

·         Malicious downloads

·         Infected USB drives

·         Exploiting software vulnerabilities

·         Via privilege escalation attacks after the initial compromise

Rootkits have the ability to:

·         Hide files/processes/registry entries

·         Intercept and modify system calls

·         Create back doors for remote access

·         Disable security software

·         Log keystrokes or steal data

There are multiple types of rootkits:

·         User-mode rootkits – can operate at the application level, can replace/modify standard system files or libraries, but are easier to detect and remove than deeper rootkits.

·         Kernal-mode rootkits – working at the operating system level, these rootkits modify the kernel (core of the OS) to intercept system calls. This can be extremely powerful and hard to detect.

·         Bootkits – these infect the bootloader or Master Boot Record, activating before the operating system loads and can even persist after OS reinstallation.

·         Firmware rootkits – target hardware level firmware, can survive operating system wipes and hard drive replacements: very difficult to remove.

How can you detect rootkits?:

·         Behavioural analysis – look for anomalies

·         Rootkit scanners – designed to search for this type of malware

·         Offline scanning – booting from a clean OS to inspect the infected system

How can you remove rootkits?:

·         Reinstall the operating system

·         Flashing firmware (in case of firmware rootkits)

·         Using specialised rootkit removal tools

Evidently, rootkits are a dangerous form of malware due to their persistence, their ability to avoid detection and the numerous ways they can get into your systems. Can your security defend against rootkits? If you’re not sure, contact Interfuture Security – we can help!

YouTube: https://youtu.be/11bIk7q1sgM