&gt;Even today a &#x27;zero day&#x27; exploit for a major platform can be dealt with though<p>But they can only be dealt with once they&#x27;re discovered by people with an incentive to fix it. The NSA <i>says</i> they weren&#x27;t using Heartbleed[1], but I can&#x27;t think of a single reason they wouldn&#x27;t lie about it. In any case, that was a massive security flaw that could have conceivably been exploited for <i>more than a decade</i>. If it affects 30 percent of systems instead of 90 percent, that seems like worthwhile hedging of bets.<p>[1] <a href="http:&#x2F;&#x2F;www.engadget.com&#x2F;2014&#x2F;04&#x2F;11&#x2F;nsa-heartbleed&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.engadget.com&#x2F;2014&#x2F;04&#x2F;11&#x2F;nsa-heartbleed&#x2F;</a>