A phishing attack is when an attacker sends you an email that contains a link to a malicious website. You click on the link because it appears to be trusted. Merely visiting the website may infect your computer or you may be tricked into signing into the malicious site with credentials from a site you trust. The attacker then has access to your username, password and any other sensitive information they can trick you into providing.
This variant of a phishing attack uses unicode to register domains that look identical to real domains. These fake domains can be used in phishing attacks to fool users into signing into a fake website, thereby handing over their login credentials to an attacker.
This affects the current version of Chrome browser, which is version 57.0.2987 and the current version of Firefox, which is version 52.0.2. This does not affect Internet Explorer or Safari browsers.
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As you can see both of these domains appear identical in the browser but they are completely different websites. One of them was registered by us, today. Our epic.com domain is actually the domain https://xn--e1awd7f.com/ but it appears in Chrome and Firefox as epic.com.
The real epic.com is a healthcare website. Using our unicode domain, we could clone the real epic.com website, then start emailing people and try to get them to sign into our fake healthcare website which would hand over their login credentials to us. We may then have full access to their healthcare records or other sensitive data.
We even managed to get an SSL certificate for our demonstration attack domain from LetsEncrypt. Getting the SSL certificate took us 5 minutes and it was free. By doing this we received the word ‘Secure’ next to our domain in Chrome and the little green lock symbol in Firefox.
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How to fix this in Firefox:
In your firefox location bar, type ‘about:config’ without quotes.
Do a search for ‘punycode’ without quotes.
You should see a parameter titled: network.IDN_show_punycode
Change the value from false to true.
Now if you try to visit our demonstration site you should see:
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Can I fix this if I use Chrome?
Currently we are not aware of a manual fix in Chrome for this. Chrome have already released a fix in their ‘Canary’ release, which is their test release. This should be released to the general public within the next few days.
Until then, if you are unsure if you are on a real site and are about to enter sensitive information, you can copy the URL in the location bar and paste it into Notepad or TextEdit on Mac. It should appear as the https://xn--….. version if it is a fake domain. Otherwise it will appear as the real domain in its unencoded form if it is the real thing.
Source: https://www.wordfence.com/blog/2017/04/chrome-firefox-unicode-phishing/