On Wed, Jan 2, 2013 at 11:36 AM, William Herrin <bill@herrin.us> wrote:
Communications using a key signed by a trusted third party suffer such attacks only with extraordinary difficulty on the part of the attacker. It's purely a technical matter.
While I agree with your general characterization of MIIM, the "extraordinary difficulty" here is not supported. As has been demonstrated, the bar for getting certs from some trusted CAs is in some cases low enough that it's not even difficult, much less extraordinarily difficult. Getting certs to a well known domain may be somewhat harder, it might be useful to see how far someone got trying to get a "mail.google.com" cert from all the commonly trusted vendors without resorting to illegal penetrations or layer 8+ hacking / social engineering / threats / intimidation / politics, but even if we exclude those threats the general envelope for not-well-known domains seems risky. Google is setting a higher bar here, which may be sufficient to deter a lot of bots and script kiddies for the next few years, but it's not enough against nation-state or serious professional level attacks. The advantage for the deterrence it can give may well be worth it anyways, for the near future. Every measure in security that does not involve the off switch is a half-measure, at least in the long term, even very large key crypto, but enough incremental steps form a useful cushion. -- -george william herbert george.herbert@gmail.com