Security Basics mailing list archives



"DNSSEC is not related to SSL/TLS security" SSL security is based on DNS. DNSSEC is security for DNS. " Again I would say my point: you *cannot* do MITM on a website if you don't have private key for the certificate on that website." Really? I have devices doing this at clients right now. " If you are NSA, you can crack the encryption with brute force and that too will take quite some time." BS "Again for god sake, this is social engineering! there is no way this can be used to MITM an existing SSL website. Well, if you can get a cert from any of the 264+ CA for citibank, that would be fault of the CA and not SSL/TLS or PKI, plus that would involve legalities. This compromise is in theory possible, but again you need access to a CA and SSL/TLS protocol is still not broken (its working as designed)" No it is not, the certs are already in the browser. I can get a .com cert from several CAs. " not possible for any guy to obtain the same " Really? I have setup a number of RAs. " Lastly, why on earth would people use electronic banking if what you claim is true and so easy to carry out?" As the issue is not one people care about. The banks have the risk. DNS and routing are the weak points. Perception. Well the simple thing here is I do this for clients from time to time. I am happy to know I am doing the impossible. Encrypted is NOT secure. It is private. These are not the same thing. If you actually believe that SSL is security, then I feel sorry for your clients. Regards, ... Dr. Craig S Wright GSE-Malware, GSE-Compliance, LLM, & ... Information Defense Pty Ltd -----Original Message----- From: Shreyas Zare [mailto:shreyas () secfence com] Sent: Thursday, 3 June 2010 4:56 PM To: craig.wright () information-defense com Cc: security-basics () securityfocus com Subject: Re: Checkpoint smart defance as IPS Hi Craig, I disagree with you my friend. And the points you are using to defend your previous claim are totally different and thus not valid for the argument. Firstly, you claim that SSL/TLS can be intercepted and MITM is possible (and effectively protocol is broken). And now you defend it citing bad implementation of SSL/TLS in browsers and social engineering. Most of your points (like phishing, fake domains etc) are social engineering and not MITM or interception for that matter. SSL/TLS is not to protect user from his/her stupidity. SSL/TLS do provide a secure channel to a site and you cannot just sniff the traffic and decrypt it (as you suggest). DNSSEC is not related to SSL/TLS security. Clients just blindly trust their ISP DNS server. DNSSEC is to make faking/spoofing a DNS reply really difficult and it will be done using digital signatures. And surely, you can attack DNSSEC too with social engineering or making the client machine trust a fake CA that you control then sign a fake reply with your private key. Again I would say my point: you *cannot* do MITM on a website if you don't have private key for the certificate on that website. However, you can be a CA and fake a certificate on the fly on your gateway, that too only when the client trusts the CA in the first place. If you are NSA, you can crack the encryption with brute force and that too will take quite some time. And ... On Thu, Jun 3, 2010 at 4:45 AM, Craig S. Wright <craig.wright () information-defense com> wrote:

Hello, I suggest that you learn to reference more than simply Wiki.

I suggested you wiki to get the basics. and wikipedia for that matter is really good. You claimed that browser only checks for domain name and totally didn't know about the handshake which involves private key of the website.

"If it was possible as you claimed, the protocol will be totally broken

and

it will be front page news article." I suggest you keep up. This is why TLS was introduced (which also has

flaws)

- which is still not used correctly either. But read on for something that matters.

1.html

Phishing is not MITM, its social engineering.

PS. A complete compromise of the CAs and DNS would not likely make a front page article. Most people do not care and it is not something that sells papers.

A persons net-banking account can be intercepted while he and his bank wont care? great!

This is also why DNS and routing are important. What do you think DNSSEC

is

really about?

DNSSEC and SSL/TLS are different things. SSL/TLS use certificates to match domain that's true but, the handshake is done as client sends a random number encrypted with public key and the server which has the private key can *only* decrypt it.

SSL is about privacy, NOT security. It was NEVER about security.

this is simply great!

How about I give you some real reading, something more than the online golden book encyclopaedia that is Wikipedia...

Thanks, I have done much more reading already.

Let's take a quote from Kurt Seifried: "Even ignoring all these problems the simple fact is that SSL certificates only identify the server to the user, they do not authenticate it. This is

a

subtle but incredibly important difference. My online bank is at

tdbank.ca,

td.ca on the other hand is owned by someone else and banktd.ca is still free. I know for example that www.openssl.org is the "official" site for OpenSSL, but what about www.openssl.de? Shouldn't that be the official

site

for OpenSSL translated into German? Well it turns out that it isn't. Do

you

trust every single root certificate in your webbrowser software? Have you even heard of "IPS SERVIDORES" (ips.es), "Saunalahden Serveri CA" (saunalahti.fi) or "SERVICIOS DE CERTIFICACION - A.N.C." (correo.com.uy)?

I

sure as heck haven't." REMEMBER - ALL CERTIFICATE AUTHORITIES ARE EQUALLY TRUSTED!!!!!!!!!!!!!!!! I have to state this again... ALL CERTIFICATE AUTHORITIES ARE EQUALLY TRUSTED!!!!!!!!!!!!!!!! Do you think your users go and check the CA and ensure it is really the

one

that the real site has used? If you think users do this, you have some learning to do. If you actually believe that you cannot obtain a signed (from a CA in IE's list) certificate for a MiTM device, you have not looked too hard. If you do not think this is a known issue, try reading some RFC's: "[Browser vendors] and users must be careful when deciding which

certificate

and certificate authorities are acceptable; a dishonest certificate authority can do tremendous damage." RFC 2246, The TLS Protocol 1.0 The 264+ root CAs trusted by Microsoft, the 166 root CAs trusted by Apple, and the 144 root CAs trusted by Firefox are capable of issuing

certificates

for any website, in any country or top level domain. See Ed Felten. "Web Certification Fail: Bad Assumptions Lead to Bad Technology". Freedom To Tinker, February 23 2010.

www.freedom-to-tinker.com/blog/felten/web-certification-fail-bad-assumptions

-lead-bad-technology.

Again for god sake, this is social engineering! there is no way this can be used to MITM an existing SSL website. Well, if you can get a cert from any of the 264+ CA for citibank, that would be fault of the CA and not SSL/TLS or PKI, plus that would involve legalities. This compromise is in theory possible, but again you need access to a CA and SSL/TLS protocol is still not broken (its working as designed)

Next, "'Packet Forensics' devices are designed to be inserted-into and removed-from busy networks without causing any noticeable interruption [.

.

. ] This allows you to conditionally intercept web, e-mail, VoIP and other traffic at-will, even while it remains protected inside an encrypted

tunnel

on the wire. Using `man-in-the-middle' to intercept TLS or SSL is essentially an attack against the underlying Diffie-Hellman cryptographic key agreement protocol [. . . ]". Packet Forensics. Export and Re-Export Requirements, 2009. www.packetforensics.com/export.safe. So - the question is... have you removed all but the "trusted" CA's from your users browsers? I doubt it. If you have, you also need to do this

EACH

and EVERY time that IE updates.

Again you need access to a CA, which a government like US can do for sure. And its again not possible for any guy to obtain the same.

Next, have a read of more than this forum. Try the TLS list from the IETF: http://www.ietf.org/mail-archive/web/tls/current/msg03928.html

From the link: "The problem: when Microsoft IIS is configured to request a client certificate after having received the request, then it WILL perform an unauthenticated request! Sending the reply back only to the authenticated client is a poor excuse for acting on an unauthenticated request." That is bad implementation of SSL, isn't it? and that too specific to a particular server. And in normal HTTPS scenario, client don't send a cert to server.

Even not paying for a certificate (which is the option for the scenario

this

derived from), you can still attack SSL/TLS: "...inject a chosen plaintext prefix into the encrypted data stream, often without detection by either end of the connection. This is possible

because

an "authentication gap" exists during the renegotiation process at which

the

MitM may splice together disparate TLS connections in a completely standards-compliant way." See

zip Finally, have you ever thought of a zero bit negotiated key. SSL with

0-bit

encryption. This can be done using a 128 bit certificate. The client to

the

IPS is clear text, but looks to the browser as being encrypted.

Again an example of bad implementation in application.

Research means more than wiki. If you use a title of researcher, it is something that you should try to do.

Thanks for the tip. But, one really needs to read basics first not matter from wiki or some another source.

Regards, ... Dr. Craig S Wright GSE-Malware, GSE-Compliance, LLM, & ... Information Defense Pty Ltd

Lastly, why on earth would people use electronic banking if what you claim is true and so easy to carry out? While there are many attacks possible in theory, implementing them practically is very difficult indeed. And such attack will depend on bad implementation issues or social engineering. Still, doing a attack based on social engineering is quite viable option but, the success rate of such attack would vary with the target population. Regards, Shreyas Zare Sr. Information Security Researcher Secfence Technologies www.secfence.com