German Govt. Skype Interception Trojans Revealed

James Hardine writes "Wikileaks has released documents from the German police revealing Skype interception technology. The leaks are currently creating a storm in the German press. The first document is a communication by the Ministry of Justice to the prosecutors office, about the cost splitting for Skype interception. The second document presents the offer made by Digitask, the German company secretly developing Skype interception, and holds information on pricing and license model, high-level technology descriptions and other detail. The document is of global importance because Skype is used by tens or hundreds of millions of people daily to communicate voice calls and Skype (owned by Ebay, Inc) promotes these calls as being encrypted and secure. The technology includes interception boxes, key forwarding trojans and anonymous proxies to hide police communications."

Comments

Man-in-the-middle against SSL?

[gnasher719]

Does anyone know how a man-in-the-middle attack against SSL, as mentioned in the article, is supposed to work?

The only possibility that I can see is to modify the browser itself, so that when the user tries to get a secure connection to www. criminals.com, the browser contacts www. police.de instead, gets a valid certificate from the police, while the police's computer then makes a secure connection to www. criminals.com.

Re:Man-in-the-middle against SSL?

[maxwell demon]

To redirect the user from www.criminals.com to www.police.de, they only have to intercept DNS calls (unless the criminals have edited their /etc/hosts or Windows equivalent, but if they get a trojan in, that shouldn't be too hard to change as well). The only thing which might be problematic is to get a valid certificate. But then, they probably can get that by just connecting themselves (which they'll do anyway if they do a man-in-the-middle). AFAIK the certificate only contains the domain name, not the server IP, so since the browser thinks it's connected with www.criminals.com, it will accept the original certificate for the fake server. I'm no SSL expert, though, so I may be missing something here.

Re:Man-in-the-middle against SSL?

[gnasher719]

mac spoofing, arp poisoning, dns spoofing, and a fake certificate Yes, I forgot that if they are able to install software on your computer, they might also be able to install a root certificate created by the police, and send you a kind-of-genuine certificate for www.terrorists.com, signed by www.police.de. Or they _might_ be able to convince a certificate authority to give them an actual, valid certificate for www.terrorists.com, which would be a bit worrying.

With a minute of thinking: The first method would be much better, because they don't need to know ahead who I am going to contact.

With another minute of thinking: My computer has for example four Verisign root certificates installed. Does that mean that Verisign (I only take them as an example) could technically install a box with a computer into the phone line 50 meters away from my house, and do a man-in-the-middle attack by creating genuine Verisign certificates for any SSL connection that I make, without breaking into my home or doing anything to my computer at all? And the only trace that I would have would be the curious fact that everyone I contact uses certificates signed by Verisign?

With a further minute of thinking: My computer has about 100 root certificates installed that came with Leopard, and similar things happen for Windows users. I have no idea where these certificates come from; I just have to trust Microsoft and Apple. If the police could convince Microsoft and Apple to put a root certificate owned by the police into their installers, then the police could read anyone's SSL connections without breaking into their homes (but breaking into their connection a bit further down the line)?