Hacker News Reader

Comment by userbinator | Hacker News Reader

I suppose they were relying on the prepending of "verify_fail" to the hostname (with an invalid character - '_') to cause the browser to fail the certificate name check, so Superfish is doing certificate checking? Shouldn't the browser then complain with a "certificate's hostname does not match the site's" warning?

...Or am I looking at this in the wrong way?

View on HN

You're close. I'm not in the business of telling people how to exploit this and am assuming those who already know were already doing it based on what would be a "best practice" (for a bad guy that is) when it comes to generating a self-signed cert.

...is it blindly copying any x509v3 attributes present on the certificate, or just the one that you seem to be carefully not mentioning? Can you email me (one is listed in my HN profile)? I just thought of a pretty horrible exploit. 2199399413f2e63e6291a3f3e60f3475518aaf88215434222c65d6bc6fe41f34

After a little more thought, it seems obvious to me now what the problem is. :-)

The shocking thing is that the certificate name matching algorithm has been standardised for over 15 years and yet those who wrote the cert generation code weren't aware of how browsers implement it.

Ding, ding, ding. ;-)

This is bumming me out. I'm really curious about what the exploit is but cannot quite put the pieces together...

Looks like someone already wrote a post about it: https://blog.filippo.io/komodia-superfish-ssl-validation-is-...

I hope to have a write-up at some point in the near future. I'm working with the vendor now to fix the vulnerability and hope they will be agreeable to a co-authored write-up once they've issued patches.

I'm really just curious & not malicious - is that string at the end of your post a hash of a key or of an exploit code?

Its probably the hash of their explanation of the exploit.

correct

Then it must be a simple to phrase exploit with only one obvious way of stating it.

The purpose of a publicized hash is that you can produce the content later and assert that you had authored it prior to the time you publicized the hash. This is proof to the extent that generating text to hit a given hash is really hard.

Reply on news.ycombinator.com