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I went to Best Buy as well today and picked up a laptop to look into this further. The Superfish software is not properly passing the validation state of the p
by patcheudor 12y ago
I went to Best Buy as well today and picked up a laptop to look into this further. The Superfish software is not properly passing the validation state of the public cert when it connects to a website like Bank of America as an example. There's no need to export their private and use it in a MitM transparent proxy. The software is simply not triggering appropriate warnings when provided an obviously fake certificate that has been generated in a way to bypass browser warnings. It's also not properly validating revoked certs. Both of these situations are very bad. Allowing any self-signed cert would lead me to believe that this could have easily been exploited in the wild without prior knowledge of this vulnerability.
I'm not going to provide a how-to guide on how to exploit users here. I have notified both Superfish and Lenovo of this issue and here's an example of the improper status pass through based on doing something that might be quite obvious to some:
This is what the browser should do when it encounters a self-signed cert delivered by an SSL/TLS MitM solution:
http://defaultstore.com/six.png http://defaultstore.com/six.png
However, it's not doing this for this self-signed public cert:
http://defaultstore.com/four.png http://defaultstore.com/four.png
Note both certs show "verify_fail." at the beginning and those who know how browser cryptography works will understand what has gone wrong with their implementation.
- patcheudor 12y agoDoes anyone have a security contact at Superfish? It looks like they don't have a security@ mailbox: "DB3FFO11OLC004.mail.protection.outlook.com rejected your message to the following email addresses: security@superfish.com Something went wrong and your message couldn't be delivered. This could be a temporary issue. Try resending the message in a few minutes. If that doesn't work, forward this message to your email admin."
- nadams 12y agoTry abuse or postmaster or one of these: http://whois.domaintools.com/superfish.com http://whois.domaintools.com/superfish.com
- patcheudor 12y agoinfo@superfish.com went through and I'd imagine that they must be reading this thread by now and can go check that mailbox to reach out to me.
- deleted 12y ago[deleted]
- userbinator 12y agoI 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?
- patcheudor 12y agoYou'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.
- ryan-c 12y ago...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
- userbinator 12y agoAfter 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.
- patcheudor 12y agoDing, ding, ding. ;-)
- mattlong 12y agoThis is bumming me out. I'm really curious about what the exploit is but cannot quite put the pieces together...
- deleted 12y ago[deleted]
- cbd1984 12y agoArticle is unmarked PDF
- cbd1984 12y agoPDF