Cryptojacking is a specialized type of cyberattack where a hacker hijacks your computer's processing power to mine cryptocurrency without your consent. Unlike typical viruses that delete files, cryptojackers steal your CPU and GPU resources, leading to system lag, overheating, and increased electricity costs. This guide will help you identify and eliminate these hidden miners.

Step 1: Monitor System Resource Usage

The most common symptom of a cryptojacker is an unexplained spike in CPU usage. Open your Task Manager (Ctrl + Shift + Esc on Windows) or Activity Monitor (Command + Space, type 'Activity Monitor' on macOS). Look for processes consuming 80% to 100% of your CPU even when no heavy applications are running. If you see a process with a strange name or your web browser consuming excessive power, it may be a mining script.

Step 2: Audit and Remove Browser Extensions

Many cryptojacking attacks are delivered through malicious browser extensions. Navigate to your browser's extension management page (e.g., chrome://extensions). Carefully review every installed item. Remove any extension that you do not recognize or that you haven't used recently. Hackers often buy popular extensions and update them with hidden mining code.

Step 3: Clear Browser Cache and Enable Script Blocking

In-browser mining occurs when you visit a compromised website. To stop this, clear your browser cache and cookies to ensure no persistent scripts remain. To prevent future infections, install an Ad-Blocker or a specialized "NoCoin" extension. These tools are designed to identify and block the specific JavaScript sequences used by crypto-mining scripts like Coinhive.

Step 4: Run a Specialized Malware Scan

Standard antivirus programs sometimes miss stealthy miners. Use a reputable anti-malware tool (like Malwarebytes) and perform a Full System Scan. For even better results, use the Microsoft Defender Offline Scan option. This allows the system to reboot and scan for malware before the operating system—and the malware—can fully load and hide its processes.

Step 5: Check for Malicious Scheduled Tasks

Cryptojacking malware often creates "Scheduled Tasks" to ensure it restarts every time you boot your computer. Open Task Scheduler on Windows and look at the "Task Scheduler Library." Search for tasks with suspicious names or those that point to AppData or Temp folders. Delete any task that triggers a script or executable you didn't personally authorize.

Step 6: Update Drivers and Patch Vulnerabilities

Miners often exploit vulnerabilities in your hardware drivers, particularly your Graphics Card (GPU) drivers, to maximize mining efficiency. Check your manufacturer's website (NVIDIA, AMD, or Intel) and install the latest drivers. Additionally, ensure your Operating System is fully updated to patch the security holes that allowed the miner to enter your system in the first place.

💡 Pro Tip: Keep your software updated to avoid these issues in the future.