In message <Pine.LNX.4.64.0511211400000.12605@twin.uoregon.edu>, Joel Jaeggli w rites:
On Mon, 21 Nov 2005, Stephen J. Wilcox wrote:
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What do you learn by looking at someone's ipsec, ssl-wrappered, or ssh tunneled traffic?
no, we're not trying to do that, you dont really think that because its encrypted it cant be decrypted do you?
I do believe (reasonably so, I think) that if I'm going have a conversation with a second party whom I already trust, that a third party will have trouble inserting themself into the path of that conversation without revealing their presence..
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you dont have to break the code if the endpoints trust sessions with you and share their encryption keys
Successfully inserting yourself in the middle requires some social-engineering or really bad protocol design. The former can be mitigated through vigilance, the later falls into the realm of peer review and security research.
The problem is "vigilance", especially as applied to non-security aware users. Here's a quick test: pick a bunch of smart, non-geek computer users and ask them what a certificate is and what a certificate authority is. Then inquire what they'd do when the web page they were looking at had some text similar to what I posted yesterday. You're absolutely right that sufficient vigilance -- coupled with good user interfaces -- should be adequate. Note my qualifiers: "sufficient", "good", "should be". Demonstrably, they're not. (A few years ago, a company I know of deployed a browser+Java-based expense voucher application. The login screen said "when you're asked if this applet should have extra permissions, just click yes, even though the pop-up warns that that could be dangerous". A security-clueful person I know complained about the bad habits this was instilling. The answer he got back was "we've checked it out; this application really is ok". Talk about unclear on the concept... That said, ssh (which you cited in another post) does a better job. It gives a very big warning that stresses the danger. By contrast, Firefox (and I think IE, though I'd have to find a Windows machine to test that) tells you that various forms of certificate problems are unlikely. The big thing ssh does is that it keeps a history -- it binds the warning to your previous history. That's a much better strategy than relying on ~80 CAs you've never heard of.
If I may paraphrase the original posters question (Ross Hosman), it was:
Do large wireless buildouts present a new security threat due to the potential to spoof AP's?
The answer to that is no, this is a threat we live with currently. We have tools to mitigate the risks associated with it.
You can say that consumers are stupid, and won't figure this out, and that may be true; however when it's starts to cost them losts money, they will sit-up take notice and buy tools to solve this problem for them, just like they do with any other security threat that goes beyond being an anoyance. probably said product will be blue, say linksys on it, and have the word vpn (among others) buried on the packaging someplace.
Given reports I've seen about public terminal usage, I'm much more skeptical. See, for example, http://www.theregister.co.uk/2005/09/21/airport_pc_security_lax/ I frequently take the train to Washington; I've occasionally noticed other PCs that appear to be looking for an access point. I've been tempted to put my machine into host AP mode (or use my travel access point -- these trains generally have AC power), run a dhcp server, and see what passwords I get. But I've never been able to convince myself that it would be legal, let alone ethical. --Steven M. Bellovin, http://www.cs.columbia.edu/~smb