What is Cryptohijacking? Definition, Detection & Protection

Cryptohijacking, also known as malicious cryptomining, is the unauthorized use of your device’s computing power to mine cryptocurrency. It silently embeds itself through infected browser extensions, malicious ads, or hidden JavaScript code—draining your system’s resources without your knowledge.

As cryptocurrency gains traction, so do the attacks targeting it. In fact, more than $2.1 billion has already been stolen in cryptocurrency-related attacks in 2025, with most losses tied to wallet compromises and phishing campaigns, according to CertiK. Cryptohijacking plays a quiet but costly role in this evolving threat landscape, often slipping past traditional defenses.

In this blog, we’ll explain the definition of cryptohijacking, how it operates, signs your system may be infected, and actionable strategies to detect and prevent it. We'll also explore how Keepnet’s xHRM Platform can help protect your organization from this rising hidden threat.

What is Cryptohijacking?

Cryptohijacking is a form of cyberattack where hackers secretly use your computer, smartphone, or server to mine cryptocurrency—without your knowledge or consent. Instead of stealing data or locking files, these attackers aim to exploit your system’s processing power to generate digital coins like Monero or Ethereum.

This is often done through malicious code hidden in websites, emails, or browser extensions, allowing the cryptomining process to run silently in the background. Unlike traditional malware, cryptohijacking doesn’t damage your data but slows down your systems, increases electricity usage, and wears out hardware over time.

It's a low-risk, high-reward tactic for cybercriminals, making it a growing concern for businesses that rely on system performance and network efficiency.

Cryptohijacking Definition

Cryptohijacking is the covert exploitation of a device’s processing power to mine cryptocurrency for an attacker’s gain. It operates discreetly, often through injected scripts or hidden software, turning victims into unwilling miners without their awareness.

How Does Cryptohijacking Work?

Cryptohijacking works by embedding malicious cryptomining scripts into websites, emails, or applications that silently activate once loaded on a device. When triggered, these scripts hijack the CPU or GPU, using the victim's processing power to mine cryptocurrency—often Monero due to its privacy features.

Attackers typically deliver the code through:

• Phishing emails with infected links or attachments.
• Compromised websites or online ads (also known as drive-by mining).
• Malicious browser extensions or third-party plugins.

Once active, the script runs in the background, draining resources and often avoiding detection by throttling usage to stay under system thresholds. Advanced cryptojacking malware may also spread across networks, infecting multiple devices to maximize mining power.

The entire process benefits the attacker financially while the victim faces system slowdowns, increased electricity bills, and potential hardware damage—making cryptohijacking a silent but serious cyber threat.

The Attack Lifecycle

The cryptohijacking attack lifecycle typically follows three key stages:

1. Delivery: The attacker plants cryptomining code via phishing emails, malicious websites, ads, or vulnerable browser extensions. This code is often JavaScript-based or embedded in malware.
2. Execution: Once the victim visits the compromised site or opens the infected file, the cryptojacking script silently activates. It begins using the device’s CPU or GPU to mine cryptocurrency—usually without any visible signs.
3. Persistence: To maintain access, attackers may use stealth techniques like code obfuscation, fileless execution, or browser pop-unders. Some scripts can spread across networks, infecting other connected systems to expand mining capacity.

This silent lifecycle allows cryptohijacking to operate undetected for long periods, generating profits for attackers while draining your resources.

High-Profile Cryptocurrency Exploit: The Bybit Hack

One of the most significant cryptocurrency-related breaches occurred on February 21, 2025, when Bybit, a major Dubai-based crypto exchange, lost 400,000 ETH—worth $1.4 billion—in a matter of minutes.

Attackers exploited a private key leak in Bybit’s hot wallet infrastructure, allowing them to quickly siphon the funds without needing access to user accounts. Though not a traditional cryptohijacking case, this incident highlights how vulnerabilities in cryptocurrency systems can lead to massive financial losses and demonstrates the lucrative motivation behind crypto-targeted cybercrime.

Bybit’s immediate response included public acknowledgment, launching a bounty program, and collaborating with authorities. Within days, the US FBI formally charged North Korean hackers, emphasizing the global scale and sophistication of threats tied to the crypto space. (Source)

Common Symptoms and Detection Techniques

Though designed to stay invisible, cryptohijacking leaves behind clear system warnings. Spotting these early symptoms is key to stopping hidden mining before it drains performance, power, and hardware lifespan. The table below outlines the most common signs that may indicate your systems are being exploited for unauthorized cryptomining.

Table 1: Key Symptoms of Cryptohijacking

Detection Techniques

To confirm a cryptohijacking infection, combine manual checks with automated defenses:

• System Monitors: Use tools like Task Manager (Windows) or Activity Monitor (Mac) to check for abnormal CPU activity.
• Network Analysis: Scan for connections to known mining pools or unusual outbound traffic.
• EDR Solutions: Endpoint Detection and Response platforms help trace unauthorized scripts and block them.
• Browser Extensions: Tools like NoCoin and minerBlock can automatically block cryptomining scripts online.
• Security Training: Educate users to report abnormal device behavior or overheating—early alerts can stop attacks from spreading.

Early detection is critical to minimizing the operational and financial impact of cryptohijacking on your business.

Protection Against Cryptohijacking

Protecting your systems from cryptohijacking requires a layered approach that combines strong cyber hygiene, technical controls, and employee awareness.

• Keep systems updated: Regularly patch operating systems, browsers, and software to close vulnerabilities exploited by mining scripts.
• Remove unnecessary extensions: Disable or uninstall unused browser extensions and third-party plugins that may act as entry points for cryptomining code.
• Use browser-based protections: Install security extensions like NoCoin or minerBlock to block cryptomining scripts before they run.
• Deploy ad blockers: Prevent malicious ads from loading mining scripts by using reputable ad-blocking tools.
• Block known mining domains: Configure DNS filters or firewalls to automatically block access to domains associated with cryptomining.
• Implement Endpoint Detection & Response (EDR): Use EDR solutions to detect unusual CPU activity, hidden mining processes, and fileless malware.
• Monitor network traffic: Watch for unexplained spikes in bandwidth or outbound connections to suspicious mining pools.
• Use anti-cryptomining tools: Run updated antivirus and anti-malware software capable of identifying cryptojacking signatures.
• Train your employees: Deliver Security Awareness Training to help staff recognize phishing attempts, unsafe downloads, and malicious browser behavior.
• Test using a Phishing Simulator: Use the Phishing Simulator to safely expose and correct risky behaviors related to common delivery methods like phishing.

By integrating these protections, businesses can reduce their exposure to cryptohijacking threats and maintain optimal system performance and security.

The Business Risks of Ignoring Cryptohijacking

Overlooking cryptohijacking can have lasting consequences for your business. While the attack may run quietly in the background, the impact is anything but minor. The table below outlines key risks organizations face when cryptojacking goes undetected.

Table 1: Key Business Risks of Cryptohijacking

Treating cryptohijacking as a minor nuisance is a costly mistake. Without a proactive strategy, it can evolve into a persistent threat that undermines both your infrastructure and your credibility.

How Keepnet Helps Protect Against Cryptohijacking

Keepnet’s xHRM Platform offers end-to-end protection against cryptohijacking by combining awareness, simulation, and rapid threat response:

• Security Awareness Training empowers employees to detect cryptojacking and phishing threats through personalized, behavior-based learning paths, engaging visual aids, and real-life scenario-based lessons.
• Phishing Simulator mimics the latest phishing and cryptojacking delivery methods with over 6,000 realistic templates, triggering instant micro-training for risky user actions.
• Incident Responder analyzes and neutralizes email-borne cryptojacking threats up to 48.6x faster through automation and integrated threat intelligence.

With Keepnet, businesses can proactively reduce cryptohijacking risks while building a resilient, security-conscious workforce.

Check out Keepnet’s Free Phishing Simulation Test to identify employee vulnerabilities and start building a stronger defense against cryptojacking threats today.