Re: [homenet] HNCP security?
On Tue, 16 Sep 2014, Tim Chown wrote: There’s obviously some interesting implications of this. One is that there are insecure wired links too! Good point. I believe we're hitting the classic secure or easy tradeoff. There is no way we automatically can detect what is home and what is not, instead there is going to have to be user interaction to say what is part of the home and what is not. For HNCP, this might mean some kind of cryptographic interaction of some kind, for instance what you suggested, having some kind of button, or perhaps having some kind of home control panel where new devices pop up and where they're authorized (or not). As was presented in.. err, London?, shared secrets are bad. To really do this properly, we need device specific keys and some kind of list of devices that are allowed to connect, perhaps by having their public keys in HNCP. I don't know. I am no security expert, but I believe we probably have to have two or three modes of security, one being unsecure that is auto everything (will give scenarios like the one Tim wrote about), one that is shared secret, but where devices need to be configured using this shared secret (protects against accidents), and a third one where PKI is used, but where user policy infrastructure is available. The third one greatly increases scope the framework required to implement. I'm not sure it would even be HNCP anymore, perhaps we need a wider view than what the HOMENET charter has in it currently. It wouldn't surprise me if we need another WG to tackle this. Perhaps it should be a more generic one based on creating a framework to handle access requests and control and how to distribute keys and other credentials, for SSH/SSL/IPSEC use, potentially? A lot of these mechanisms probably already exists, but they need to be put together and told how to interact. -- Mikael Abrahamssonemail: swm...@swm.pp.se___ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
Re: [homenet] HNCP security?
Tim Chown t...@ecs.soton.ac.uk wrote: On 16 Sep 2014, at 14:52, Michael Richardson mcr+i...@sandelman.ca wrote: I think that we can assume that wired links are secure. The only time we care if wireless is secured is when we want to form an adjacency over the wireless link. I think it is acceptable to refuse to form an adjancency over an insecured wireless link. A little side story… ... To cut a long story short, my powerline adaptors had formed a single network with powerline adaptors in a neighbour’s house. Yes, this is an issue, and you could equally have done this over cable modem. Or if you plugged a layer-2 ethernet/802.11 extender in to a wired port of your router, and your neighbour did the same thing. It's always possible to defeat things; the question is whether or not your 1% situation should mean that we have no security for 99% of the other times it works fine? That's why I suggest that the wire permits a TOFU bootstrap, not that it's forever insecure. I don't see how your buttons, etc. would have permitted anything, since that would have been about the wifi. My understanding is that a new generation of powerline ethernet now actually uses 15.4 MACs with a different PHY, and in fact runs Zigbee over it, for exactly the situation you mentioned. -- ] Never tell me the odds! | ipv6 mesh networks [ ] Michael Richardson, Sandelman Software Works| network architect [ ] m...@sandelman.ca http://www.sandelman.ca/| ruby on rails[ ___ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
Re: [homenet] HNCP security?
On 09/17/2014 06:37 AM, Michael Richardson wrote: Michael Thomas m...@mtcc.com wrote: I further suggest that if two routers have wireless that they might well have a WPA2/PSK available to them, and that they can and SHOULD use something derived from that key to authenticate each other. Could be over IKEv2, yes. If I have more than one SSID, which PSK should the router use? Whichever ones authenticates the message. The PSK is not transmitted. I'm about to send a routing update, or whatever message. Which WPA2 key does the router use? And if it's a simple derivation, that means that anybody with the right PSK can derive that key and participate in routing whether we want them to or not, right? That is, where is the authz? That's the nature of a PSK, yes. I want to control people who I give access to my home network to participate in routing or not. Overloading network access control with access to control plane modification sounds like a bad idea to me. If you wanted to overload the use of a key, it might better to derive a key from their admin logins. But it would be best of all to not overload anything. Mike ___ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
Re: [homenet] HNCP security?
On 09/16/2014 11:31 PM, Mikael Abrahamsson wrote: As was presented in.. err, London?, shared secrets are bad. To really do this properly, we need device specific keys and some kind of list of devices that are allowed to connect, perhaps by having their public keys in HNCP. I don't know. I am no security expert, but I believe we probably have to have two or three modes of security, one being unsecure that is auto everything (will give scenarios like the one Tim wrote about), one that is shared secret, but where devices need to be configured using this shared secret (protects against accidents), and a third one where PKI is used, but where user policy infrastructure is available. The third one greatly increases scope the framework required to implement. I'm not sure it would even be HNCP anymore, perhaps we need a wider view than what the HOMENET charter has in it currently. Global symmetric keys certainly have their problems, but using public keys have their own. Namely, if I want to enroll a new device each other currently enrolled device needs to know about the public key of the new enrollee. For 2 devices, that's possibly manageable but for more I really don't want to run around my house looking for every homenet device to enroll the new one. If we were to do that, it might be nice to have a distributed database of homenet devices such that I only had to enroll it on one of my homenet devices, and then it's distributed to the rest. Mike ___ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
Re: [homenet] HNCP security?
On 9/17/14, 10:24 AM, Michael Richardson wrote: Michael Thomas m...@mtcc.com wrote: If I have more than one SSID, which PSK should the router use? Whichever ones authenticates the message. The PSK is not transmitted. I'm about to send a routing update, or whatever message. Which WPA2 key does the router use? You don't use that key for that. You use a key that IKEv2 built for you, using that key to authenticate the IKEv2 session. The result shows up in a list of peers, if you have turned off TOFU, then you'd have to authorize each one. Which is that key here? I thought you said previously that that key was somehow derived from a WPA2 PSK. If not, I don't understand how IKE helps with the enrollment problem. References to TOFU would be appreciated too... google is not immediately helpful. Mike ___ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
Re: [homenet] HNCP security?
On 18/09/2014 02:58, Michael Thomas wrote: On 09/16/2014 11:31 PM, Mikael Abrahamsson wrote: As was presented in.. err, London?, shared secrets are bad. To really do this properly, we need device specific keys and some kind of list of devices that are allowed to connect, perhaps by having their public keys in HNCP. I don't know. I am no security expert, but I believe we probably have to have two or three modes of security, one being unsecure that is auto everything (will give scenarios like the one Tim wrote about), one that is shared secret, but where devices need to be configured using this shared secret (protects against accidents), and a third one where PKI is used, but where user policy infrastructure is available. The third one greatly increases scope the framework required to implement. I'm not sure it would even be HNCP anymore, perhaps we need a wider view than what the HOMENET charter has in it currently. Global symmetric keys certainly have their problems, but using public keys have their own. Namely, if I want to enroll a new device each other currently enrolled device needs to know about the public key of the new enrollee. For 2 devices, that's possibly manageable but for more I really don't want to run around my house looking for every homenet device to enroll the new one. If we were to do that, it might be nice to have a distributed database of homenet devices such that I only had to enroll it on one of my homenet devices, and then it's distributed to the rest. I don't think that's a nice to have. I think it's an unavoidable requirement, and it has to require at most trivial human intervention. (Don't shoot me, but this happens to be a must-have for autonomic networking too.) Brian ___ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
Re: [homenet] HNCP security?
On Wed, 17 Sep 2014, Michael Thomas wrote: Global symmetric keys certainly have their problems, but using public keys have their own. Namely, if I want to enroll a new device each other currently enrolled device needs to know about the public key of the new enrollee. For 2 devices, that's possibly manageable but for more I really don't want to run around my house looking for every homenet device to enroll the new one. If we were to do that, it might be nice to have a distributed database of homenet devices such that I only had to enroll it on one of my homenet devices, and then it's distributed to the rest. That is exactly what I tried to propose. -- Mikael Abrahamssonemail: swm...@swm.pp.se ___ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
