A new browser extension called Behave! will alert you if a website uses scripts to perform local or private IP addresses on your network.
When browsing the web, scripts embedded in web pages can be used not only to scan a visitor's computer for open TCP ports, but also to launch attacks on other devices on the network.
In May, it was discovered that known sites like eBay, Citibank, TD Bank and many more scan a visitor's computer to locate programs remote access of Windows running on it.
While for good reason, users who have found that something like this happens consider that firstly it is annoying and secondly that their privacy is being violated.
Even worse, hackers could use it JavaScript embedded in sites to perform DNS Rebinding attacks.
These attacks are commonly used against router, IoT devices and even other internal computers known to use vulnerable software.

Enter the Behave browser extension!
Created by Stefano Di Paola, co-founder, CTO and Chief Scientist of MindedSecurity, the Behave extension! The browser was born as an experiment to warn users of sites that abuse the functions of the browser to perform local attacks or scans on a visitor's computer
During installation, the Behave extension! will monitor scripts that attempt to access IP addresses belonging to the following blocks:
- Loopback addresses IPv4 127.0.0.1/8
- Loopback IPv6 addresses :: 1/128
- Private IPv4 networks 10.0.0.0/8 - 172.16.0.0/12 - 192.168.0.0/16
- Unique local IPv6 fc00 addresses :: / 7
If something is detected, the extension icon will display a red indicator and, when pressed, the activity performed by the site will appear.
The extension can also be set to display browser notifications when such an action is detected.
It should be noted that one error in the extension it may report false DNS attacks and Di Paola has corrected the error and is waiting for Google's approval in the new version.
The Behave expansion! is available for both Chrome and Firefox.
For those interested in being notified of possible abusive behavior by visiting websites, Behave! is an interesting extension for installation.