Posts Tagged: punycode


26
Nov 18

Half of all Phishing Sites Now Have the Padlock

Maybe you were once advised to “look for the padlock” as a means of telling legitimate e-commerce sites from phishing or malware traps. Unfortunately, this has never been more useless advice. New research indicates that half of all phishing scams are now hosted on Web sites whose Internet address includes the padlock and begins with “https://”.

A live Paypal phishing site that uses https:// (has the green padlock).

Recent data from anti-phishing company PhishLabs shows that 49 percent of all phishing sites in the third quarter of 2018 bore the padlock security icon next to the phishing site domain name as displayed in a browser address bar. That’s up from 25 percent just one year ago, and from 35 percent in the second quarter of 2018.

This alarming shift is notable because a majority of Internet users have taken the age-old “look for the lock” advice to heart, and still associate the lock icon with legitimate sites. A PhishLabs survey conducted last year found more than 80% of respondents believed the green lock indicated a website was either legitimate and/or safe.

In reality, the https:// part of the address (also called “Secure Sockets Layer” or SSL) merely signifies the data being transmitted back and forth between your browser and the site is encrypted and can’t be read by third parties. The presence of the padlock does not mean the site is legitimate, nor is it any proof the site has been security-hardened against intrusion from hackers.

A live Facebook phish that uses SSL (has the green padlock).

Most of the battle to combat cybercrime involves defenders responding to offensive moves made by attackers. But the rapidly increasing adoption of SSL by phishers is a good example in which fraudsters are taking their cue from legitimate sites.

“PhishLabs believes that this can be attributed to both the continued use of SSL certificates by phishers who register their own domain names and create certificates for them, as well as a general increase in SSL due to the Google Chrome browser now displaying ‘Not secure’ for web sites that do not use SSL,” said John LaCour, chief technology officer for the company. “The bottom line is that the presence or lack of SSL doesn’t tell you anything about a site’s legitimacy.”

The major Web browser makers work with a number of security organizations to index and block new phishing sites, often serving bright red warning pages that flag the page of a phishing scam and seek to discourage people from visiting the sites. But not all phishing scams get flagged so quickly.

I spent a few minutes browsing phishtank.com for phishing sites that use SSL, and found this cleverly crafted page that attempts to phish credentials from users of Bibox, a cryptocurrency exchange. Click the image below and see if you can spot what’s going on with this Web address:

This live phish targets users of cryptocurrency exchange Bibox. Look carefully at the URL in the address bar, and you’ll notice a squiggly mark over the “i” in Bibox. This is an internationalized domain name, and the real address is https://www.xn--bbox-vw5a[.]com/login

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8
Mar 18

Look-Alike Domains and Visual Confusion

How good are you at telling the difference between domain names you know and trust and impostor or look-alike domains? The answer may depend on how familiar you are with the nuances of internationalized domain names (IDNs), as well as which browser or Web application you’re using.

For example, how does your browser interpret the following domain? I’ll give you a hint: Despite appearances, it is most certainly not the actual domain for software firm CA Technologies (formerly Computer Associates Intl Inc.), which owns the original ca.com domain name:

https://www.са.com/

Go ahead and click on the link above or cut-and-paste it into a browser address bar. If you’re using Google Chrome, Apple’s Safari, or some recent version of Microsoft‘s Internet Explorer or Edge browsers, you should notice that the address converts to “xn--80a7a.com.” This is called “punycode,” and it allows browsers to render domains with non-Latin alphabets like Cyrillic and Ukrainian.

Below is what it looks like in Edge on Windows 10; Google Chrome renders it much the same way. Notice what’s in the address bar (ignore the “fake site” and “Welcome to…” text, which was added as a courtesy by the person who registered this domain):

The domain https://www.са.com/ as rendered by Microsoft Edge on Windows 10. The rest of the text in the image (beginning with “Welcome to a site…”) was added by the person who registered this test domain, not the browser.

IE, Edge, Chrome and Safari all will convert https://www.са.com/ into its punycode output (xn--80a7a.com), in part to warn visitors about any confusion over look-alike domains registered in other languages. But if you load that domain in Mozilla Firefox and look at the address bar, you’ll notice there’s no warning of possible danger ahead. It just looks like it’s loading the real ca.com:

What the fake ca.com domain looks like when loaded in Mozilla Firefox. A browser certificate ordered from Comodo allows it to include the green lock (https://) in the address bar, adding legitimacy to the look-alike domain. The rest of the text in the image (beginning with “Welcome to a site…”) was added by the person who registered this test domain, not the browser. Click to enlarge.

The domain “xn--80a7a.com” pictured in the first screenshot above is punycode for the Ukrainian letters for “s” (which is represented by the character “c” in Russian and Ukrainian), as well as an identical Ukrainian “a”.

It was registered by Alex Holden, founder of Milwaukee, Wis.-based Hold Security Inc. Holden’s been experimenting with how the different browsers handle punycodes in the browser and via email. Holden grew up in what was then the Soviet Union and speaks both Russian and Ukrainian, and he’s been playing with Cyrillic letters to spell English words in domain names.

Letters like A and O look exactly the same and the only difference is their Unicode value. There are more than 136,000 Unicode characters used to represent letters and symbols in 139 modern and historic scripts, so there’s a ton of room for look-alike or malicious/fake domains.

For example, “a” in Latin is the Unicode value “0061” and in Cyrillic is “0430.”  To a human, the graphical representation for both looks the same, but for a computer there is a huge difference. Internationalized domain names (IDNs) allow domain names to be registered in non-Latin letters (RFC 3492), provided the domain is all in the same language; trying to mix two different IDNs in the same name causes the domain registries to reject the registration attempt.

So, in the Cyrillic alphabet (Russian/Ukrainian), we can spell АТТ, УАНОО, ХВОХ, and so on. As you can imagine, the potential opportunity for impersonation and abuse are great with IDNs. Here’s a snippet from a larger chart Holden put together showing some of the more common ways that IDNs can be made to look like established, recognizable domains:

Image: Hold Security.

Holden also was able to register a valid SSL encryption certificate for https://www.са.com from Comodo.com, which would only add legitimacy to the domain were it to be used in phishing attacks against CA customers by bad guys, for example. Continue reading →