利用 Unicode Domain 釣魚,以及 Chrome 與 Firefox 的解法

一個多禮拜前引起蠻多討論的一篇文章,利用 Unicode Domain 釣魚的方法:「Phishing with Unicode Domains」。

由於這是幾乎完美的攻擊,所以被提出來後 (Security: Whole-script confusable domain label spoofing) 有不少討論:

This bug was reported to Chrome and Firefox on January 20, 2017 and was fixed in the Chrome trunk on March 24. The fix is included in Chrome 58 which is currently rolling out to users.

comment 8 提到:

We do have a whitelist. Essentially you're suggesting that we remove Cyrillic and Greek characters from the list. I'm not sure we want to go down that path.

在新版的 Chrome 58 已經「修正」了這個問題:

Firefox 的討論在「IDN Phishing using whole-script confusables on Windows and Linux」這邊,一開始就直接把票給關了 XDDD:

Indeed. Our IDN threat model specifically excludes whole-script homographs, because they can't be detected programmatically and our "TLD whitelist" approach didn't scale in the face of a large number of new TLDs. If you are buying a domain in a registry which does not have proper anti-spoofing protections (like .com), it is sadly the responsibility of domain owners to check for whole-script homographs and register them.

We can't go blacklisting standard Cyrillic letters.

If you think there is a problem here, complain to the .com registry who let you register https://www.xn--80ak6aa92e.com/ .

Gerv

Status: NEW → RESOLVED
Last Resolved: 3 months ago
Flags: needinfo?(gerv)
Resolution: --- → WONTFIX

然後一個月前被提出來看看 Chrome 怎麼做:

Gerv/Valentin, is this something we can/should align with Chromium on?

目前唯一的解法是改 flag,把所有的 Unicode Domain 直接當作一般的 domain 來處理,列出像是 www.xn--80ak6aa92e.com 的網址。