MONEY: a terrorist group hell-bent on "raising terror" can accumulate the amount required...
TIME: terrorist groups have all the time in the world...
FACILITIES: terrorists are really good at improvising which would also make the money problem less of a problem (my grammar sucks hahaha bear with me
)...
SKILL: I would bet they have/could find people skilled enough...
PATIENTS/TEST SUBJECTS: us (what better way to test it than to release it at some highly populated place and let the police/government/hospitals count how many are infected/dead to see how deadly it is)
it wouldn't be that easy to "make" the virus but once they know how to what's gonna stop them from trying to make one..