Forbid non-LAN web to access LAN

Latest Version

Version
0.6.2
Update
March 22, 2024
Size
37.49KiB
Developer
garywill.github.io
Category
Users
345
Rating
1 ★
Manifest Version
2
Web Store Status
Languages Support
English
See more
Permissions
WebRequest
WebRequestBlocking
*://*/*
Ws://*/*
Wss://*/*
Ftp://*/*
ContextMenus
Storage
See more

LAN port scan forbidder Extension

Forbid untrusted web to scan localhost or LAN.

## Source Code Repo
https://github.com/garywill/LAN-port-scan-forbidder

## What

Webs can try to fetch `127.0.0.1:xxxx` or `192.168.Y.Z:xxxx` to scan your open ports in LAN.

Although browsers have cross-domain protections, webs can't read response contents, **but** can still see the connection succeeds or fails.

There're already reports that some websites using that as tracking fingerprint.

> A web for testing: http://samy.pl/webscan/

## So

Forbid any website behaviors trying to connect to your LAN or localhost, if user is visiting the website via their domains or public IP addresses. (Read the source code `background.js` to see the logic)

> Using JS library [whitequark/ipaddr.js](https://github.com/whitequark/ipaddr.js) (MIT License) v2.0.0 to judge IP range.


### Notification

User can enable notification. When untrusted web tries to access private network and get blocked, will show up notification.

### Fallback operation

If user find a web broken, user can temporary set this addon disabled via toolbar button for:

- this one tab
- this one tab and new tabs opened by this tab
- this one window (Firefox only)
- globally

(above can be set as keyboard shortcuts)

there's showy toolbar button badge indicating disabling status.

## Cases when web LAN scan is properly used

Not all LAN-port-scan are evil.

- Some manufacturers provide web for user's browser to scan LAN for their product that need updating.

- Some softwares use `127.0.0.1` communication to interact between native program and web.

## Disclaimer

This open souce addon comes with no warranty. Use on you own risk!
Read more

Source Manifest.json

{"update_url": "https://clients2.google.com/service/update2/crx", "name": "LAN port scan forbidder", "description": "Forbid non-LAN web to access LAN", "manifest_version": 2, "version": "0.6.2", "homepage_url": "https://github.com/garywill/LAN-port-scan-forbidder/", "author": { "name": "Garywill", "url": "https://garywill.github.io" }, "permissions": [ "webRequest", "webRequestBlocking", "*://*/*", "ws://*/*", "wss://*/*", "ftp://*/*", "contextMenus", "storage" ], "optional_permissions": [ "notifications" ], "icons": { "128": "icon.png" }, "background": { "page": "background.html" }, "browser_action": { "default_icon": "icon_gray.png", "default_title": "LAN port scan forbidder" }, "commands": { "_execute_browser_action": { "description": "Click toolbar button" }, "toggle_t" : { "description": "Toggle for one tab" }, "toggle_h" : { "description": "Toggle for one tab and new tabs opened by it" }, "toggle_global" : { "description": "Toggle globally enable/disable" } }, "options_ui": { "page": "options.html" }}
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How to download and manually install LAN port scan forbidder extension for Chrome

Looking for a way to install LAN port scan forbidder extensions for Chrome, you can search for them in the Chrome Web Store, clicking the "Add to Chrome" button, and following the straightforward process.

However, you may need to install LAN port scan forbidder extensions manually, this article outlines two simple methods to effortlessly install LAN port scan forbidder extensions, whether they come as unpacked folders in compressed formats like .zip or as .crx files.

Method 1: Download LAN port scan forbidder extension and manually install through Drag &Drop

If you ever need to manually install a LAN port scan forbidder extension for Chrome, don't worry, it's a simple process. Just follow these easy steps, and you will have your extension ready to use in no time.

Step 1: Download the LAN port scan forbidder Extension by clicking the "Download CRX" button on the website.

Look for the LAN port scan forbidder extension you wish to install. Go to the website and download the LAN port scan forbidder extension package, which is usually a .CRX file and comes in a zipped file. Here ".crx" file is the format for LAN port scan forbidder extension that contains all the data.

Step 2: Extract &Arrange Files

Once the file is downloaded, extract that file into its own folder. Similarly, give that extension files a permanent home. In other words, keep it in a folder that you don't accidentally delete it because these files will be needed to make that extension work.

Step 3: Go to the Chrome Extensions Page

Open Google Chrome and in the address bar, type chrome://extensions; it will open the Google Chrome extensions page. Make sure that "My extensions" is selected in the sidebar.

Step 4: Drag and Drop the Extension

Now, go to the folder where you extracted the LAN port scan forbidder extension and drag &drop the extension file from there anywhere onto the extension page within Google Chrome.

Step 5: Complete the Installation

Once you drag and drop the extension file, follow the steps that Google Chrome takes you through. Similarly, if the extension file is of .crx file format, you will be required to review the permissions and then add the extension.

Now, you can manage that added extension as you would like to with any other Chrome extension that you added through Chrome Webstore. Its icon will also appear in the Google Chrome Menu on the right side of the address bar once you activate it.

Method 2: Download LAN port scan forbidder extension for Chrome and install in Developer Mode

This is another method to install LAN port scan forbidder extension manually, but the twist is that here, you install by enabling the developer mode option provided in Google Chrome. This mode is commonly used for testing extensions or running unpublished tools.

Step 1: Download the LAN port scan forbidder extension file

Select and download the LAN port scan forbidder extension by clicking the 'Download CRX' button on the website.

Step 2: Extract the downloaded contents

Convert the file to a ZIP file if it is in CRX format then extract the LAN port scan forbidder extension zip file or folder that you downloaded. Make sure you extract it using the same folder name and keep it safely in another folder, so you don't delete it by mistake. The extracted folder will be needed to keep your LAN port scan forbidder extension running.

Step 3: Open Chrome Extension Setting Page

In the address bar of Google Chrome, type chrome://extensions and open the Chrome Extension Page.

Step 4: Enable Developer Mode

After opening the Chrome Extension page, look at the top right side, and you will find the toggle option of "Developer mode."Simply enable that developer mode option.

Step 5: Load the Unpacked Extension

Once you enable the developer mode option, you will see the menu of Load Unpacked, Pack Extensions and Update. From that, select the option "Load unpacked."

Step 6: Select the Extension Folder

Once the pop-up opens upon clicking Load unpacked, select the LAN port scan forbidder extension directory and click on the "Select Folder "button.

Step 7: Confirm and Install

After you select an extension folder of a Google Chrome extension you're installing manually, confirm its installation for the final time and let the installation complete.

Conclusion

Here we've made a step-by-step guide on How to manually install LAN port scan forbidder extension in 2 ways. We hope this guide proves helpful.

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