What is a modular delayed action virus? In Ghost in the Shell: Stand Alone Complex series, the modular delayed action virus is mentioned quite often. Is there any explanation for what it actually is or does?
A modular delayed action virus is nothing particular. It's a virus, that is uploaded and takes action later, with a modular design, which means, that it's kind of generic, so it can be modified easily.

The term is used quite often, because different characters use such viruses very often - So there's nothing someone could say about "what it does".