How to Block Cryptojacking: Browser Extensions That Stop…

KEY TAKEAWAYS

1. SonicWall recorded 1.06 billion cryptojacking incidents globally during 2023, representing a 659% increase over 2022 totals, with Europe experiencing the sharpest regional surge at 1,046 percent.
2. MinerBlock operates as an open source browser extension using dual detection through blacklist blocking of known mining domains and behavioral analysis that identifies suspicious script activity patterns automatically.
3. No Coin is a retired cryptojacking-blocking extension that is no longer maintained. Users can instead use current browser protections and ad-blocking lists to help block cryptocurrency mining scripts.
4. Organizations have reported six-figure cloud computing bills from cryptojacking incidents, including cases where attackers compromised cloud credentials and launched unauthorized mining operations on victim infrastructure.
5. Browser-based cryptojacking injects mining code through compromised websites or malicious advertisements, exploiting visitors' CPU resources to mine Monero and other privacy-focused cryptocurrencies without obtaining user consent.

Cryptojacking hijacks computing power from unsuspecting users to mine cryptocurrency without their knowledge. SonicWall recorded 1.06 billion cryptojacking incidents during 2023, a 659% increase over 2022. Cryptojacking can allow attackers to monetize compromised computing resources without the direct demands associated with some other forms of cybercrime.Browser extensions offer the most accessible first line of defense against web-based cryptojacking attacks. Tools like MinerBlock and maintained ad-blocking lists target and block unauthorized mining scripts.This article examines how these extensions work alongside broader detection and prevention strategies available for individual users.

How Browser-Based Cryptojacking Works

Browser-based cryptojacking delivers mining scripts through compromised websites or malicious advertisements running in browsers. Visitors load a webpage containing embedded JavaScript code that begins mining cryptocurrency immediately. The scripts typically mine Monero and other privacy coins because their mining algorithms favor standard CPU resources.The mining code runs silently inside the browser tab, consuming processor cycles without any visible notification. Users notice symptoms including slower device performance, rapid battery drain, and system overheating. Unexplained CPU usage spikes during periods of low apparent activity can be a sign of cryptojacking and warrant further investigation.SonicWall's 2024 Cyber Threat Report, covering full-year 2023 data, reveals stark regional differences in cryptojacking attack volumes globally. Europe recorded a 1,046% increase in incidents during 2023 compared to the previous year. North America saw a 596% rise while Latin America experienced 116% growth in the same reporting period.Cloud cryptojacking can produce six-figure computing bills for organizations when unauthorized mining runs undetected on cloud infrastructure.

Browser Extensions That Block Mining Scripts

MinerBlock operates as an open-source browser extension available for Chrome and Firefox installations. The tool uses a dual detection approach combining blacklist domain blocking with behavioral script analysis. Its blacklist contains known mining pool addresses and CoinHive domains, while behavioral detection catches previously unknown mining scripts.No Coin was an early browser extension designed to block cryptocurrency mining, but its repository was archived in 2020 and the extension is no longer maintained. Current users can instead rely on browser protections and maintained ad-blocking lists to help block browser-based mining threats.Malwarebytes Premium blocks CoinHive and other cryptocurrency miners as part of its broader security protection suite. The company explained its blocking rationale clearly in public documentation provided to users."The reason we block Coinhive is because there are site owners who abuse this service by refusing to ask for their users' permission to start running CPU-gorging applications on their systems," Malwarebytes stated regarding its blocking policy.Google banned all cryptocurrency mining extensions from the Chrome Web Store in April 2018, specifically. That policy followed the discovery of extensions that secretly mined while claiming other primary functionality purposes. Users should download mining blockers only from verified open source repositories like GitHub.

Detection Methods and Prevention Strategies

Task Manager and Activity Monitor tools reveal abnormal CPU usage caused by hidden mining scripts. Users should check processor utilization during periods when no demanding applications are actively running on devices. Sustained CPU usage above eighty percent during browser-only sessions indicates potential cryptojacking activity requiring immediate investigation.Ad blockers provide supplementary protection by filtering advertisements that deliver mining code payloads to users. Extensions like uBlock Origin block known malicious advertising networks that distribute cryptojacking scripts broadly. Combining a dedicated mining blocker with an ad blocker creates a layered defense against multiple delivery vectors simultaneously.Disabling JavaScript entirely prevents code injection but severely limits normal browsing functionality for users. Chrome and Firefox both support site-specific JavaScript permissions through their built-in security settings.Enterprise environments face elevated risk from cloud-based cryptojacking targeting virtual machine infrastructure. In the USAID incident, attackers password-sprayed an administrator account without multifactor authentication and ran up nearly $500,000 in Azure charges. Regular audits of cloud credentials and resource monitoring remain essential prevention measures.

Regulatory Implications

Cryptojacking constitutes unauthorized access to computing resources under existing computer fraud statutes across jurisdictions. The U.S. Computer Fraud and Abuse Act provides federal prosecution authority for unauthorized mining operations. The European Union's revised Network and Information Systems Directive imposes mandatory incident reporting requirements on affected organizations operating critical digital infrastructure.

What's Next?

Cryptojacking techniques continue evolving toward fileless malware and WebAssembly-based miners that evade traditional detection methods. Browser vendors are integrating native resource usage monitoring to alert users about suspicious script behavior automatically. Open source extension communities maintain updated blocklists that remain the fastest response mechanism against newly discovered mining domains.

FAQs

What is cryptojacking? Cryptojacking is the unauthorized use of someone's computing device to mine cryptocurrency without their knowledge or consent, typically through browser scripts or installed malware running silently.How does MinerBlock stop cryptojacking? MinerBlock uses dual detection, combining a blacklist of known mining domains with behavioral analysis that identifies suspicious script patterns, blocking both known and previously unidentified mining code.What are the signs of cryptojacking on a device? Common indicators include noticeably slower device performance, rapid battery drain on laptops or phones, system overheating, and unexplained CPU usage spikes during periods of low application activity.Did Google ban crypto mining extensions? Google banned all cryptocurrency mining extensions from the Chrome Web Store in April 2018 after discovering extensions that secretly mined cryptocurrency while advertising completely different primary functionality to users.How many cryptojacking attacks occurred in 2023? SonicWall recorded 1.06 billion cryptojacking incidents globally in 2023, representing a 659% increase compared to 2022 totals across all monitored network traffic. Can ad blockers prevent cryptojacking attacks? Ad blockers provide supplementary protection by filtering malicious advertisements that deliver mining scripts, while maintained blocking lists can also help prevent browser-based mining scripts from loading. Dedicated tools such as MinerBlock can provide additional protection against known mining threats. What cryptocurrency do cryptojackers mine most? Cryptojackers primarily mine Monero and other privacy-focused cryptocurrencies because their mining algorithms perform efficiently on standard consumer CPU hardware without requiring specialized GPU equipment.

References

1. SonicWall 2024 Cyber Threat Report: Full-Year 2023 Cryptojacking Threat Intelligence Data and Analysis
2. StationX Malware Statistics 2026: Cryptojacking Incidents, Regional Growth, and Threat Trends
3. SentinelOne How to Prevent Cryptojacking: Detection Methods and Security Best Practices
4. MinerBlock Open Source Browser Extension for Cryptojacking Detection and Blocking