Removing rootkit malware can be complex due to its stealthy nature, as it hides deep within your system and evades standard antivirus scans. Below is a detailed, step-by-step guide to help you eliminate rootkits effectively:

1. Isolate Your System
   Disconnect from the Internet: Prevent the rootkit from communicating with attackers or downloading additional malware.
   Avoid Using the Infected System: Refrain from accessing files, browsers, or applications, as this may trigger further damage.
2. Boot into Safe Mode (or Safe Mode with Networking if Needed)
   Safe Mode starts your system with minimal drivers and services, making it harder for the rootkit to operate.
   For Windows:
   Press the Power button during startup and repeatedly tap F8 or Shift + F8 (for newer versions) to access the Advanced Boot Options.
   Select Safe Mode with Networking (if you need to download tools) or Safe Mode.
   For macOS:
   Restart your Mac and hold the Shift key until the login screen appears.
   Log in to Safe Mode (this disables non-essential startup items).
   For Linux:
   Boot from a live USB or DVD and use a minimal Linux environment (e.g., Kali Linux) to avoid running the infected OS.
3. Use Dedicated Rootkit Removal Tools
   Standard antivirus tools may not detect rootkits. Use specialized software:

Windows

Malwarebytes:
Download the latest version in Safe Mode with Networking.
Run a Full Scan (Malwarebytes includes rootkit detection in premium versions).
Sophos Free Rootkit Remover:
A standalone tool designed to detect and remove hidden rootkits.
TDSSKiller (Kaspersky):
Specifically targets the TDSS rootkit family but works on other types too.
Microsoft Safety Scanner:
A free, downloadable tool for deep system scanning.

macOS

Malwarebytes for Mac:
Scans for macOS-specific rootkits and malware.
ESET Cyber Security Pro:
Offers advanced rootkit detection for Mac systems.

Linux

Chrootkit Scanner (rkhunter):
A command-line tool to scan for known rootkit signatures.
“`bash
sudo apt-get install rkhunter
sudo rkhunter –update
sudo rkhunter –check

Chkrootkit:  
Another CLI tool for detecting rootkits.  

bash
sudo apt-get install chkrootkit
sudo chkrootkit
“`

4. Use Antivirus Software in Offline Mode
   Some rootkits disable online scanning. Use offline scanners (bootable media):
   Kaspersky Rescue Disk:
   Create a bootable USB/DVD and scan your system without loading the infected OS.
   Bitdefender Rescue Mode:
   Accessible via Bitdefender’s interface, it restarts your PC into a secure environment for scanning.
   Trend Micro Rescue Disk:
   Boot from media to scan and clean the system.
5. Manually Remove Suspicious Files and Processes (Advanced Users Only)
   Only attempt this if you are familiar with system files.
   Identify Malicious Processes:
   On Windows: Open Task Manager (Ctrl + Shift + Esc) and look for unfamiliar processes. Right-click > Open File Location to check their source.
   On macOS/Linux: Use ps -aux in Terminal to list processes. Flag unusual CPU/memory usage.
   Delete Suspicious Files:
   Rootkits often hide in:
   Windows: C:\Windows\System32, C:\ProgramData, or random-named folders in AppData.
   macOS: /Library/LaunchAgents, /private/var, or hidden files starting with ..
   Caution: Do not delete system files! Use the tools above to safely remove identified malware.
   Clean Registry (Windows):
   Open Registry Editor (regedit) and back up your registry first.
   Search for keys related to the rootkit (e.g., random strings in HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run).
6. Update Your System and Software

• After removal, install all OS and application updates to patch vulnerabilities exploited by the rootkit.
  For Windows: Use Settings > Update & Security.
  For macOS: Go to System Preferences > Software Update.
  For Linux: Run package manager updates (e.g., sudo apt update && sudo apt upgrade).

4. Restore Your System (If Manual Removal Fails)
   System Restore (Windows):
   Use a restore point created before the infection (access via Control Panel > Recovery).
   Time Machine (macOS):
   Restore your system from a backup taken prior to the rootkit attack.
   Fresh OS Installation:
   If all else fails, back up essential data (ensure backups are clean!) and reinstall the OS. Format your drives to eliminate deep-rooted malware.
5. Strengthen Your Security Post-Removal
   Install a Reliable Antivirus: Use tools like Norton, Kaspersky, or Bitdefender with real-time rootkit protection.
   Enable Firewall and Auto-Updates: Prevent future infections by keeping security layers active.
   Avoid Suspicious Content: Stay away from untrusted websites, email attachments, and pirated software.
   Regular Backups: Use external drives or cloud services to back up data, ensuring you can recover without relying on a compromised system.

Key Notes
Do Not Panic: Rootkits are serious but not unbeatable. Take your time and follow steps carefully.
Seek Professional Help: If you’re unsure, consult a cybersecurity expert or use your antivirus provider’s support services.
Verify Cleanliness: After removal, rescan your system with multiple tools to confirm no traces remain.

By combining specialized tools, cautious manual steps, and system hardening, you can effectively remove rootkit malware and protect your device from future threats.