A new browser extension published dubbed Behave! that warns the user if the website tries to perform a port scan or launch DNS based attacks.
The web sites port scanning issue came into light after a script found on the eBay website that performs local port scans on a user computer to check for remote access.
The extension is available to download for Firefox and Chrome browsers. You can also disable or enable alerts.
https://github.com/mindedsecurity/behave
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