It’s possible to hijack an SSL connection that’s forwarded through a network you control, if the user and browser combination aren’t extra vigilant to verify they ended up at the requested domain. (Actually, sslstrip can generally hijack traffic on adjacent networks by pretending to be the router, but it’s even easier and more reliable if it runs on the router.)
This hijacking is possible even using best-available off-the-shelf browsers. If you control the browser, of course it’s even easier to hijack SSL; you just fake the padlock icon and send the traffic wherever you want.
I’m not saying Amazon does anything like this with the Kindle, but I am curious how to verify that SSL traffic originating in the Kindle browser is actually secure end-to-end like SSL is supposed to be.
I got curious about this and used my Kindle’s 3G connection to retrieve some pages from an HTTPS server I control, and looked at the access log to see where the access came from.
Using the Kindle 3G connection (from Argentina!), the requesting IP address was 220.127.116.11, which back-resolves as kindle-user.whispernet.com according to nslookup. (That name doesn’t forward-resolve to anything, which is suspicious network management on Amazon’s part.) Running a traceroute to this address shows packets entering Amazon’s network and doesn’t show details past that.
Setting the Kindle to use Wi-Fi instead of 3G and then requesting the page again, the requesting IP address was 18.104.22.168, which back-resolves as cpe-190-55-119-242.telecentro-reversos.com.ar — clearly in Argentina.
As another comparison point: Using my cell phone on 3G, with Wi-Fi disabled, to request the same page yielded an access from IP address 22.214.171.124, which doesn’t have a reverse DNS entry; traceroute shows this address as clearly in Argentina, however. (The cell phone was on Claro’s network; I don’t know what 3G network the Kindle was using, and it’s not necessarily the same.)
What this means is that not only does Amazon control the Kindle hardware and software, but for 3G (Whispernet) connections, they apparently route all the traffic through Amazon’s network and datacenter. It’s probably cheaper for them to negotiate bulk data contracts with a bunch of 3G networks that way, but it would make me feel better if I saw a direct route from where I’m sitting to where I’m going, like I do with the cell phone.
(Note 1: this is all moot since again, if you control the browsing software and hardware as Amazon does, there are easier ways to cheat, and I do trust Amazon not to do any of this cheating.)
(Note 2: proxying all wireless traffic, regardless of where your device is, through the home datacenter is also essentially how all Blackberry network access works, and also how Opera Mini works, right?)