Slashdot Mirror
SSLStrip Now In the Wild
An anonymous reader writes "Moxie Marlinspike, who last week presented his controversial SSL stripping attacks at Black Hat Federal, appears to have released his much-anticipated demonstration tool for performing MITM attacks against would-be SSL connections. This vulnerability has been met with everything from calls for more widespread EV certificate deployment to an even more fervent push for DNSSEC."
You could also try to read about it... The problem is not with SSL, it's with an attacker redirecting the traffic before it is in SSL, as your typical banking session usually start in plain HTTP. People then fail to understand the visual clues given by their browser. This attack is a nice technical MITM/social engineering mix, countermeasures are not really purely technical, if banks stopped to be cheap and did all their serving over HTTPS there would not be any HTTP traffic to modify in the first place...
This attack does not break SSL in any way. It simply tricks users into entering sensitive information into unencrypted context.
The solution is user education. We need to train users to look for the browser padlock icon. We need to add browser extensions that heuristically detect credit card numbers being entered into unencrypted sites and to warn the user. We need to train users to click "no" on security dialogs when they appear. We need to tell users that a padlock icon a website puts next to a form is unacceptable. We need to train users to be vigilant, because nasty people are trying to steal their information.
I'd like to see fewer people using self-signed certificates that train users to ignore SSL warnings. I'd like to see public service advertisements. I'd like to see basic computer safety classes in public schools. User education is the only hope we have against stupid users!
The fault lies partly with browsers too. Firefox, particularly, should never have toned-down the non-EV SSL user-interface --- sure, making EV special is fine, but allowing sites to spoof the SSL UI with a favicon is unacceptable. People have been saying this ever since Firefox 3 came out, but maybe now someone will pay attention to us.
A site should never lead the user to type sensitive information into a form on an unencrypted page, even if the form's data goes to an encrypted location when submitted. Doing this trains users to be lazy. What's even worse is trying to alleviate users very correct fears by putting a padlock icon next to the form. That's even worse: doing that trains users to believe that a website can signal its own trustworthiness apart from the browser UI, and that could have disastrous consequences.
I have a technical solution, but it won't be popular: browsers should display a warning when submitting a form on an unencrypted page to an encrypted URL. Since web designers are afraid warnings will spook users, they'll switch to making the form-entry pages encrypted as well.
We don't need an alternative to SSL. We need browsers to implement proper UI. The user MUST be made aware if clicking a button would transmit a password in cleartext. The user MUST be made aware exactly which domain they are connected to during an SSL session. On a large busy screen, a tiny bit of text in a corner is the wrong way to do this.
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