Simply as a matter of CONCEPT (and handwaving the specifics aside for convenience), one of the few ways that Virus™ "took on a life of its own" (and consumed everything it came in contact with) requires something that sounds stupid until you really think about it.
Software defined hardware.
The only way the Cymbeline Silicon Life-Form would be able to "do the things it does" essentially requires software defined hardware ... which then recursively modifies in ways that further evolve the software (wash, rinse, repeat).
And while such computer hardware might be common at higher tech levels (such as the TL=12+ referred to above), I can just as easily imagine that lower tech hardware (TL=11-) would be increasingly less susceptible.
I mean ... seriously ... is Virus™ supposed to be able to take over vacuum tube arrays (as a silicon based life form)?
What about
Spintronics?
How about
Hydromechanical Computing?
Or let's just go for broke here ...
Analog Computing, rather than Digital?
My point being that Virus™ shouldn't have been able to have
THE Skeleton Passkey to EVERY computer in existence ... and yet, that's the way that it is portrayed ... hence why magic/psionics and other "cheat codes" are required for it to be able to do what it does in the OTU (which a lot of people reject, just like they do The Wave™). It's functionally a "zombie apocalypse" for computing that quickly goes Skynet (and extremely insane!).