Netcraft Extension

Netcraft Extension

Comprehensive site information and protection from phishing and malicious JavaScript when browsing the web

Netcraft Extension promo image
What is Netcraft Extension?

Netcraft Extension is a versatile Firefox add-on that enhances your online security. It provides comprehensive information about the websites you visit, offers proactive protection from phishing sites and malicious JavaScripts. Created by an English Internet services company, Netcraft, the extension also features credential leak detection and has the capability to offer detailed site reports to help users make informed decisions about the safety of the sites they visit.

Stats date:
Users: 4,571 ▲ 33
Rating: 4.42 (36)
Version: 2.1.0 (Last updated: 2023-11-21)
Creation date: 2005-10-06
Weekly download count: 173
Firefox on Android: No
Manifest version: 3
  • scripting
  • storage
  • tabs
  • webNavigation
  • webRequest
  • webRequestBlocking
Host permissions:
  • <all_urls>
Size: 787.96K
Email: Click to see
Risk impact: High risk impact
Risk likelihood: Moderate risk likelihood

Other platforms

Netcraft Extension
Netcraft Extension (v1.18.1)
4.48 (150) 63,965
Not available on Edge

The Netcraft Extension is a tool allowing easy lookup of information relating to the sites you visit and providing protection from phishing and malicious JavaScript.

What's new in v2.0.1? • Updated the extension to the latest web extension API, MV3. The extension must now be manually granted permission to perform its blocking. • Expanded coverage of malicious JavaScript blocking. • Removed possibility of the extension having compatibility issues with sites. • Removed outdated information from site information popup.

Key Features:

• Protection against phishing sites — The Netcraft anti-phishing community is effectively a giant neighbourhood watch scheme, empowering the most alert and most expert members to defend everyone within the community. As soon as the first recipients of a phishing mail report it, we can block it for all users of the extension providing an additional level of protection from Phishing. Netcraft processes reports of fraudulent URLs from a diverse variety of sources and proactively searches for new fraudulent sites.

• Protection against malicious JavaScript — Prevent your credit card details from being stolen by shopping site skimmers or your computer's processing power being harvested by web miners. Netcraft has been detecting shopping site skimmers, web miners, and other malicious JavaScript since 2017. The extension blocks sites that we have found to be compromised with malicious JavaScript. Additionally, it detects JavaScript that we have identified as being malicious, blocks pages that use it from loading, and automatically reports them to Netcraft to protect the rest of the community.

• Credential leak detection – Even if you come across a shopping site skimmer that Netcraft has not yet detected, the extension can still work to protect your card details. Credential leak detection inspects outgoing requests on the fly, blocking them if they carry your sensitive data to potentially malicious external domains. The compromised site is then blocked and reported to Netcraft.

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User reviews
User reviews summary
These summaries are automatically generated weekly using AI based on recent user reviews. Firefox Browser Add-ons does not verify user reviews, so some user reviews may be inaccurate, spammy, or outdated.
  • Keeps users informed about bad sites
  • Quickly reacts to new sites
  • Doesn't slow down or lock up the computer
  • Offers other protections
  • Site info constantly refreshes/blinks
  • False positives on certain websites
  • No obvious way to challenge results
Most mentioned
  • Keeps users informed about bad sites
  • Quickly reacts to new sites
  • False positives on certain websites
  • No obvious way to challenge results
View all user reviews
Risk impact

Netcraft Extension is risky to use as it requires a number of sensitive permissions that can potentially harm your browser and steal your data. Exercise caution when installing this add-on. Review carefully before installing. We recommend that you only install Netcraft Extension if you trust the publisher.

Risk likelihood

Netcraft Extension is probably trust-worthy. Prefer other publishers if available. Exercise caution when installing this add-on.

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