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Law Enforcement Appliance Subverts SSL

wired.com

11–20 of 42 posts

Re: Law Enforcement Appliance Subverts SSL

#11
post #3

Earlier quoted context omitted.

Looks like all it does is replace a SSL MITM proxy.

The real bad guys can just use symmetric encryption, with keys distributed by mail or by hashing parts of certain books. It's the typical end-user going to their banking site or reading their email that's most vulnerable to such devices. China might be a top customer.

If the real bad guys are smart, they're just going to use SSL, with a single static private CA.

Re: Law Enforcement Appliance Subverts SSL

#12
post #6

Shouldn't it be possible to detect when this is happening, and who's issuing the certificates? We need a plugin that snarfs the certificates as they hit your browser, and a web service to log them to (send the SHA256 of the cert, and if it's not already there, send the complete contents of the cert). I'm game if someone else is.

http://www.cs.cmu.edu/~perspectives/firefox.html

Re: Law Enforcement Appliance Subverts SSL

#13
post #4

If a CA is issuing bad certificates then they need to be removed from the default CA list. Mozilla was worried about this with China a little while ago. http://www.freedom-to-tinker.com/blog/felten/mozilla-debates... The real news will be if anyone can prove that a default CA has been compelled by court order to generate a fake certificate.

1. A lot of businesses comply with law enforcement requests without a court order.

2. If you are capable of doing this, you are also capable of attacking the automated verification methods that low-assurance/domain-validated CAs use. For example, if you can spoof DNS for a domain, you can send the CA MX records that direct all validation email to the domain to your own server. Or, if you're a government, you can work with the target's email provider and/or domain name registrar and/or anybody else willing to help; then they could get forged certificates without the cooperation or knowledge of the CA.

Re: Law Enforcement Appliance Subverts SSL

#14
post #6

Shouldn't it be possible to detect when this is happening, and who's issuing the certificates? We need a plugin that snarfs the certificates as they hit your browser, and a web service to log them to (send the SHA256 of the cert, and if it's not already there, send the complete contents of the cert). I'm game if someone else is.

http://www.cs.cmu.edu/~perspectives/firefox.html

There you go!

Re: Law Enforcement Appliance Subverts SSL

#15
post #9

The appliance itself doesn't seem that important. The big thing I take from the article is law enforcement needs to: "persuade one of the Certificate Authorities — using money, blackmail or legal process — to issue a fake certificate for the targeted website." If you can get a forged certificate from a trusted cert provider, then there is a bunch of ways to do this. The box is just a convenience.

If a CA is compelled to issue a false certificate by court order, this destroys their credibility completely. If I ran a CA, I'd rather face the consequences, and let the court ask another listed CA, rather than destroy my entire business model.

Watch what happens when we find out which CA's did this. My money is on "they do not go out of business". Give it a few months.

Re: Law Enforcement Appliance Subverts SSL

#17
post #15
post #9

Earlier quoted context omitted.

If a CA is compelled to issue a false certificate by court order, this destroys their credibility completely. If I ran a CA, I'd rather face the consequences, and let the court ask another listed CA, rather than destroy my entire business model.

Watch what happens when we find out which CA's did this. My money is on "they do not go out of business". Give it a few months.

Especially with Americans new found willingness to accept overreaching law enforcement measures. So long as one of the right trigger words (terrorism, children) is used, the average purchaser of certificates won't blink at the idea that law enforcement completely subverted the chain of trust that enables their customers to believe they are dealing with who it says on the certificate.

Re: Law Enforcement Appliance Subverts SSL

#19
post #5

The appliance itself doesn't seem that important. The big thing I take from the article is law enforcement needs to: "persuade one of the Certificate Authorities — using money, blackmail or legal process — to issue a fake certificate for the targeted website." If you can get a forged certificate from a trusted cert provider, then there is a bunch of ways to do this. The box is just a convenience.

Yes - I thought this was a cryptographic breakthrough, but it's just people breaking promises.

That, and it demonstrates how bad the default SSL trust model is. If the gmail.com certificate came from Thawte yesterday and comes from the Department of Defense or CNNIC today, your browser will happily accept it without warning.

Re: Law Enforcement Appliance Subverts SSL

#20
So to counter this kind of MITM attack the browser (or other SSL-app) should allow the user to store the certificate/root certificate for a certain site, and then provide a warning when it doesn't match the stored one. Doesn't sound that hard, maybe even an extension to Fx could do that?
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