On: Most software already has a “golden key” backdoor:...

[zokier]

I think the timeframe OP alludes predates works best with Internet Explorer and Office viruses by a decade.

[uxp → zokier]

Oh, so decades before semantic versioning, where an update was shrink-wrapped in a cardboard box on a shelf at the nearest Computer City and resulted in an entire night of floppy disk swapping instead of working?

Those really were the days...