Working around USPS Web Tools SSL Certificate Errors

Our internal application calls the USPS Web Tools APIs to generate customs forms automatically for us. This integration was working untouched and swimmingly for about a year, when suddenly this morning it started throwing exceptions saying that the SSL certificate at the USPS servers is not trusted. Sure enough, visiting the https://secure.shippingapis.com/ShippingAPI.dll URL in Google Chrome or Internet Explorer popped up an untrusted certificate warning message.

It would appear that they are using “AAA Certificate Services” now (not sure if they were using this before or if some Windows Update removed this intermediate certificate, but the error suddenly started occurring on all machines in the office), which doesn’t have its root certificate installed in Windows XP.

Here’s the workaround: Download the AAA Intermediate certificate file. Right-click, Install, click Next a few times, and then you should be right as rain again.

I could go on about the USPS Web Tools in general, but suffice to say that this is but one example of how it Simply Does Not Work.