SSL Cert Weaknesses Exposed By Comodo Breach

snydeq writes "InfoWorld's Woody Leonhard delves deeper into the Comodo SSL scandal and finds the breach calls into question the integrity of the SSL certification process itself. 'While the press has focused on the sensational fact that Comodo's site was hacked from an Iranian IP address, we really should be asking three questions: How did somebody working with an Iranian IP address get a username and password from Comodo with enough clearance to create SSL certificates? Why did Comodo issue SSL certificates for google.com, live.com, yahoo.com, mozilla.org, and skype.com? Why are browser updates used to revoke SSL certificates?'"

Comments

Peter Guttman's take

[kensan]

He makes some interesting points on EFF's SSL Observatory mailinglist: https://mail1.eff.org/pipermail/observatory/2011-March/000138.html

Re:Regarding question 1

[flonker]

They didn't buy it. They created it through the reseller process. OpenSRS, for example, requires that all IPs that have access to the domain registration process are registered beforehand. That would have stopped this attack cold. Comodo didn't even have so much as a "wow, that's funny, this /24 has never logged in before, and is registered to a country I don't have any resellers in." Also, a lot of people seem to believe that automated systems should blacklist high profile targets from being automatically granted certificates.

Re:SSL certs are both over-trusted and under-trust

[Rigrig]

I agree it's stupid how browsers show self-signed certificates as more dangerous than plain HTTP.

The difference between paid-for certificates and self-signed certificates means more than just who promises authenticity though: The certificate's signature can be checked against the certificate shipped with the browser, thus preventing MITM attacks.

Basically:

1. HTTP: everybody on the network can read your stuff, including passwords etc. They don't even need to perform a MITM attack. With a simply MITM attack they can also alter content.
2. Self-signed HTTPS: your traffic isn't that easily sniffable anymore, but an attacker can perform a MITM attack to read/alter your data. He'd intercept all your browsers' requests, including the certificate, and replace them with his own.
3. CA-signed HTTPS: an attacker can't perform a MITM attack, because intercepting the certificate request means it's signature won't match with the CA-cert that your browser shipped with.

Thus paid-for certificates mean you won't get MITM'd, the part where the CA also verifies identities is just bonus.

Re:Thanks Comodo

[thue]

The beauty of it is that even if you do not buy your certificate from Comodo, you are still just as vulnerable to false certificates in your name from Comodo (Or any other of the ~650 CAs).

Re:SSL certs are both over-trusted and under-trust

[Confusador]

But it's still better than http, because it's not trying to solve the vulnerability you're complaining about. Plain HTTP is vulnerable to MITM and ANY SORT OF EAVESDROPPING. Self signed certs are vulnerable to MITM, and eavesdropping (I believe) if the 3rd party catches all of the key exchange. CA signed certs are vulnerable to neither.

Claiming that self-signed certs are the same as plain-old-http is as ridiculous as claiming that self-signed certs are secure. They won't protect you against an even mildly determined attacker, but they will stop e.g. the Google van from picking up your email. (Yes, that would have been a problem users could have fixed easily, but do you trust them? More layers of security, when easily implemented, are better.)