What is Cryptojacking? Definition, Detection & Protection

In 2025, cybercriminals have already stolen over $2.1 billion in cryptocurrency-related attacks, with the majority of losses stemming from wallet compromises and phishing campaigns (Source). While these high-profile breaches dominate headlines, a more insidious threat operates silently in the background: cryptojacking.

Cryptojacking involves unauthorized use of a device's computing power to mine cryptocurrency, often without the user's knowledge. This covert activity can lead to degraded system performance, increased electricity costs, and accelerated hardware wear, posing significant risks to both individuals and organizations.

In this blog, we'll delve into the definition of cryptojacking, explore how it operates, identify signs of infection, and provide actionable strategies to detect and prevent it. We'll also highlight how Keepnet's xHRM platform can fortify your organization's defenses against this escalating threat.

What is Cryptojacking?

Cryptojacking is a cyberattack where malicious actors secretly use your device’s CPU or GPU to mine cryptocurrency without your knowledge or consent. Instead of stealing sensitive data or encrypting files, attackers focus on exploiting computing resources to generate digital coins such as Monero.

This type of attack usually starts through phishing emails, compromised websites, or software embedded with hidden cryptomining scripts. Once the code is triggered, it runs quietly in the background, reducing system performance, increasing electricity consumption, and causing hardware to wear out faster.

Since the attack does not trigger obvious alerts, it can continue undetected for long periods, making it an attractive and profitable method for cybercriminals.

Cryptojacking Definition

Cryptojacking is the covert use of a device’s computing power to mine cryptocurrency for a cybercriminal’s benefit. It functions silently, often through hidden scripts or malicious software, turning unsuspecting users into unknowing participants in illicit cryptomining operations.

How Does Cryptojacking Work?

Cryptojacking works by embedding malicious cryptomining scripts into websites, emails, or software applications that silently activate once they’re loaded onto a device. When triggered, these scripts hijack the CPU or GPU, using the victim’s processing power to mine cryptocurrency—commonly Monero due to its privacy-focused design.

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 operates quietly in the background, draining system resources while staying under detection thresholds by throttling CPU usage. Advanced cryptojacking malware may even spread across internal networks, infecting other devices to amplify mining output.

The entire process generates profit for the attacker while the victim suffers from sluggish system performance, higher electricity bills, and increased hardware wear, making cryptojacking a hidden but impactful cybersecurity threat.

The Attack Lifecycle

The cryptojacking attack lifecycle typically unfolds in three main stages:

• Delivery: The attacker injects cryptomining code through phishing emails, compromised websites, online advertisements, or malicious browser extensions. The payload is usually JavaScript-based or hidden within malware-laced downloads.
• Execution: When the victim interacts with the malicious content - by clicking a link, opening an attachment, or visiting an infected page - the cryptojacking script activates silently. It begins utilizing the device’s CPU or GPU to mine cryptocurrency without any visible symptoms.
• Persistence: To remain active, attackers apply stealth tactics such as code obfuscation, fileless execution, or persistent browser activity. In some cases, the script can laterally move within a network, infecting other connected devices to scale the mining operation.

This quiet, continuous cycle enables cryptojacking to evade detection for extended periods, allowing attackers to reap financial rewards while gradually degrading system performance and increasing operational costs.

HJINX-0132: Cryptojacking via DevOps Exploits

In 2025, a cryptojacking campaign named JINX-0132 was discovered targeting internet-exposed DevOps systems like Docker, Gitea, and HashiCorp Nomad. The attackers searched for systems that were poorly configured or left unprotected, then injected cryptomining scripts to secretly mine cryptocurrency.

Instead of creating their own tools, the attackers downloaded publicly available cryptomining software from GitHub. This made the attacks harder to trace and easier to launch. They used these tools to run the XMRig miner, a popular program for mining Monero.

What made this campaign especially dangerous was its ability to take over systems that controlled hundreds of connected machines. By doing so, the attackers gained access to massive computing power - enough to cost tens of thousands of dollars per month if rented legally. (Source)

This case highlights how cryptojackers can exploit weakly secured systems to run large-scale mining operations, putting organizations at risk of high operational costs and reduced system performance.

Common Symptoms and Detection Techniques

While cryptojacking is designed to stay hidden, it often leaves behind noticeable signs. Identifying these symptoms early can help stop unauthorized cryptomining before it impacts system performance, increases electricity costs, or causes long-term hardware issues. The table below highlights common indicators that a device may be affected by cryptojacking.

Table 1: Common Symptoms of Cryptojacking

Detection Techniques

To detect cryptojacking activity, use a mix of manual inspections and automated tools to identify unusual behavior and block threats early:

• System Monitors: Check Task Manager (Windows) or Activity Monitor (Mac) for high CPU or GPU usage caused by unknown background processes.
• Network Analysis: Monitor for unusual outbound traffic or connections to known cryptocurrency mining pools.
• EDR Solutions: Endpoint Detection and Response tools can identify, trace, and neutralize hidden cryptomining scripts across your network.
• Browser Extensions: Install script-blocking tools like NoCoin or minerBlock to prevent mining scripts from executing during web browsing.
• Security Awareness Training: Teach employees to recognize overheating devices, unexpected slowdowns, or browser anomalies—early user reporting can help stop attacks quickly.

Spotting these signals early can help reduce system strain, protect your infrastructure, and avoid hidden financial losses from cryptojacking.

Protection Against Cryptojacking

Defending against cryptojacking requires a layered approach that includes system hardening, proactive monitoring, and employee awareness.

• Keep systems updated: Patch operating systems, browsers, and software to close vulnerabilities used by mining scripts.
• Remove unnecessary extensions: Disable or uninstall unused browser add-ons that could serve as entry points.
• Use browser protections: Install tools like NoCoin or minerBlock to block cryptomining scripts online.
• Deploy ad blockers: Prevent malicious ads from launching mining code in the background.
• Block mining domains: Use DNS filters or firewalls to deny access to known cryptomining servers.
• Implement EDR: Detect and stop hidden mining processes and fileless malware using Endpoint Detection and Response tools.
• Monitor network traffic: Look for unusual bandwidth usage or connections to mining pools.
• Run anti-cryptomining tools: Use updated antivirus software capable of spotting cryptojacking behaviors.
• Train your employees: Provide Security Awareness Training to help staff spot phishing and unusual device behavior.
• Use Phishing Simulators: Test employee readiness with simulated phishing linked to cryptojacking scenarios.

These steps help reduce cryptojacking risks and keep your systems running securely and efficiently.

Failing to address cryptojacking can quietly drain your business resources and expose deeper security flaws. Although the attack often operates in the background, its consequences can be severe. The table below outlines the main risks organizations face when cryptojacking goes undetected.

Table 2: Key Business Risks of Cryptojacking

Treating cryptojacking as a minor issue is a risky oversight. Without timely detection and mitigation, it can escalate into a long-term threat that impacts both your operations and your reputation.

How Keepnet Helps Protect Against Cryptojacking

Keepnet’s xHRM Platform delivers full-spectrum defense against cryptojacking by combining employee training, realistic threat simulations, and automated incident response:

• Security Awareness Training equips employees with the skills to recognize cryptojacking tactics, phishing attempts, and suspicious system behavior through interactive modules and real-life simulations.
• Phishing Simulator replicates the most current cryptojacking and phishing attack vectors using over 6,000 realistic templates, helping to identify vulnerable users and trigger targeted micro-trainings.
• Incident Responder detects and mitigates email-based cryptojacking threats significantly faster using automated workflows and integrated threat intelligence.

With Keepnet, organizations can detect early warning signs, close human risk gaps, and stop cryptojacking attacks before they cause financial or operational damage.

Start strengthening your defenses today with Keepnet’s Free Phishing Simulation Test to uncover hidden risks and build a security-first culture.