Wouldn't they just do what all browser-version-specific websites have done in the past and have an http landing page with a conditional redirect? User agent is IE6, and you progress to ie6.bankofamerica.com. User agent is Chrome/Firefox, progress to webpage with browser version warning and download link for IE6.
Well, just looking at the Bank of America example, they don't seem to use HSTS in their landing page. How widespread is HSTS? How long is the expiry period typically set for (I would guess a long time?)
Does anyone still use browser bookmarks?
Actually, just thinking about it, it might be even simpler than this. If Bank of America wanted to, couldn't they still host their redirect landing page over SSL with a valid non-Symantec certificate, and then redirect to the ie6.bankofamerica.com page which will continue to use the bad Symantec cert? If switching certs for their web infrastructure was really difficult and they didn't want to do it, they could just build a simple little front-end web server with a valid certificate to redirect people to an IE6 download page or ie6.bankofamerica.com.
This made me cry a little. But on a more serious note, every existing link on the Web is essentially a bookmark, so I don't think we can ignore that when discussing impact. (Though I'm betting all incoming requests could be rerouted more easily than telling your customers to (and how to) install a cert...)
HSTS is currently used by 2.8% of all websites, up from 1.2% this time last year. [1] If people are using Qualys SSL Labs tool to check their "grade", they won't be awarded an A+ grade unless their HSTS max-age is at least 6 months [2], so I'm going to assume the average is somewhere close to that due to how common usage of that tool is.
My grandma still uses browser bookmarks, but I have no none-anecdotal source for this.
BoA could absolutely do all the things you just mentioned, but all of them are more difficult than simply replacing their certificate using Comodo or some other trusted root CA.
BoA could absolutely do all the things you just mentioned, but all of them are more difficult than simply replacing their certificate using Comodo or some other trusted root CA.
That depends on the design of the site and their business policies. I agree though - for any sensible organization switching certs is going to be easier. But if that was really the case here, why were they asking Symantec for special favours?
