Comments on: TLS Renegotiation Test http://netsekure.org/2009/11/tls-renegotiation-test/ random noise generator Mon, 28 Nov 2011 08:33:59 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Attacks « Aggressive Virus Defense http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-2585 Attacks « Aggressive Virus Defense Thu, 11 Aug 2011 21:46:20 +0000 http://netsekure.org/?p=156#comment-2585 [...] TLS renegotiation attack is explained at educatedguesswork.org, and tested at netsekure.org. Note that there are many mitigation methods (alunj blog, F5 community post), so simply having a [...] [...] TLS renegotiation attack is explained at educatedguesswork.org, and tested at netsekure.org. Note that there are many mitigation methods (alunj blog, F5 community post), so simply having a [...]

]]> By: Kai Engert http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-2071 Kai Engert Wed, 22 Jun 2011 20:15:41 +0000 http://netsekure.org/?p=156#comment-2071 Nasko, I don't have your email. If you want, please cancel this message, and let's discuss by email first. Thanks for explaning your intention. I also tested using an old client to a patched server, and I get different results than you you report. If I use an old client, connect to twitter.com:443, send one byte of data, then request a renegotiation, then wait for something to happen... nothing happens. The server ignores my request for a handshake. I think this means the server is fine. How does your test work? Do you send your request after the second handshake? Nasko, I don’t have your email. If you want, please cancel this message, and let’s discuss by email first.

Thanks for explaning your intention. I also tested using an old client to a patched server, and I get different results than you you report.

If I use an old client, connect to twitter.com:443, send one byte of data, then request a renegotiation, then wait for something to happen… nothing happens. The server ignores my request for a handshake. I think this means the server is fine.

How does your test work? Do you send your request after the second handshake?

]]> By: Nasko http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-2060 Nasko Wed, 22 Jun 2011 14:02:43 +0000 http://netsekure.org/?p=156#comment-2060 Hi Kai, The tests has two pieces to it - check if client initiated renegotiation is supported, which was the initial easiest attack vector and check if secure renegotiation is supported. While a server supporting secure renegotiation is great, if the client connecting to it is not patched, the connection is still vulnerable. As such, I kept both pieces of information in the test, such that you can get the full picture out. I could update the actual post, but hopefully this comment will clear things up. Nasko Hi Kai,
The tests has two pieces to it – check if client initiated renegotiation is supported, which was the initial easiest attack vector and check if secure renegotiation is supported. While a server supporting secure renegotiation is great, if the client connecting to it is not patched, the connection is still vulnerable. As such, I kept both pieces of information in the test, such that you can get the full picture out. I could update the actual post, but hopefully this comment will clear things up.
Nasko

]]> By: Kai Engert http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-2054 Kai Engert Wed, 22 Jun 2011 10:34:43 +0000 http://netsekure.org/?p=156#comment-2054 Hi. What about patched servers that use secure renegotiation? Twitter.com is an example. I think such sites are fine. Although you report the "site supports secure renegotiation", you also include the warning "unpatched servers ... are vulnerable". When not reading carefully, one might get the impression that the patched server is still vulnerable. I understand your test is from 2009, when disabling renegotiation was the only remedy. However, if you continue to operate this test, maybe you want to consider to remove this warning for patched servers? Regards, Kai Hi. What about patched servers that use secure renegotiation? Twitter.com is an example. I think such sites are fine. Although you report the “site supports secure renegotiation”, you also include the warning “unpatched servers … are vulnerable”. When not reading carefully, one might get the impression that the patched server is still vulnerable. I understand your test is from 2009, when disabling renegotiation was the only remedy. However, if you continue to operate this test, maybe you want to consider to remove this warning for patched servers? Regards, Kai

]]> By: Nasko http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-2049 Nasko Tue, 21 Jun 2011 21:10:51 +0000 http://netsekure.org/?p=156#comment-2049 Sure, I'll contact you over email. Sure, I’ll contact you over email.

]]> By: orel http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-2045 orel Tue, 21 Jun 2011 16:45:12 +0000 http://netsekure.org/?p=156#comment-2045 Hi Nasko, I try to build a nagios plugins for this check. Would it be too much if i ask you to send me your source code whatever language you used. Thanks in advance, Orel Hi Nasko,
I try to build a nagios plugins for this check.
Would it be too much if i ask you to send me your source code whatever language you used.
Thanks in advance,
Orel

]]> By: Nasko http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-123 Nasko Mon, 26 Apr 2010 16:18:56 +0000 http://netsekure.org/?p=156#comment-123 I've emailed you with details, so let's keep in touch and see how I can help you with your project. I’ve emailed you with details, so let’s keep in touch and see how I can help you with your project.

]]> By: Nasko http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-122 Nasko Mon, 26 Apr 2010 16:17:39 +0000 http://netsekure.org/?p=156#comment-122 Yes, I am only testing client initiated renegotiation. It says so on the page itself : ). Server initiated renegotiation depends on a bunch of factors, so it is hard to produce a generic test. Yes, I am only testing client initiated renegotiation. It says so on the page itself : ). Server initiated renegotiation depends on a bunch of factors, so it is hard to produce a generic test.

]]> By: Nipun http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-111 Nipun Sat, 24 Apr 2010 21:01:56 +0000 http://netsekure.org/?p=156#comment-111 We are trying to make the use of X-ignore in HTTP header to simulate the attack. And, it seems like you use telnet to get the output here. Are you only testing for Client-initiated renegotiation ? We are trying to make the use of X-ignore in HTTP header to simulate the attack. And, it seems like you use telnet to get the output here. Are you only testing for Client-initiated renegotiation ?

]]> By: Nipun http://netsekure.org/2009/11/tls-renegotiation-test/comment-page-1/#comment-110 Nipun Sat, 24 Apr 2010 20:59:05 +0000 http://netsekure.org/?p=156#comment-110 Hey Nasko, This is pretty cool. We are a bunch of grad students who are trying to simulate the TLS renegotiation vulnerability in virtual testbed environment. I just stumbled on to your link today, 2 days before the final presentation of our project. Can you please share the source code of this Renegotiation Test with us ? We hope that we will get back to you with a better implementation useful for our project as well as for putting up on your website. Let me know if you have any questions. Thanks and regards, Nipun Hey Nasko,

This is pretty cool. We are a bunch of grad students who are trying to simulate the TLS renegotiation vulnerability in virtual testbed environment. I just stumbled on to your link today, 2 days before the final presentation of our project.

Can you please share the source code of this Renegotiation Test with us ? We hope that we will get back to you with a better implementation useful for our project as well as for putting up on your website.

Let me know if you have any questions.

Thanks and regards,

Nipun

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