Forgive the grammar lesson, but actually, no it's not. It's a mass
noun, not a count noun. As is "software," by the way. Another common
example of a mass noun is "furniture." You can talk about "furniture,"
but not "furnitures."
For a technical discussion of the difference between the two types of
nouns, see
http://en.wikipedia.org/wiki/Mass_noun
And by the way, several years ago my wife and I took a vacation in
China, and studied Chinese a little for a few months before the trip.
One of the things our teacher pointed out was that Chinese nouns were
very different from English in that every Chinese noun required a
qualifier, describing the kind of thing it is. So you can't say "a
paper," you have to say "a piece of paper," you can't say "a wood,"
you have to say "a stick of wood," and so on. Our teacher didn't know
the technical terms "mass noun" and "count noun," but she was
essentially saying that all Chinese nouns are mass nouns, which they
are. And since mass nouns are fairly common in English, Chinese isn't
as different from English in that respect as she thought it was.
So what it all comes down to is that, since they are mass nouns, you
can never say "malwares" or "softwares." You can talk about "malware"
or "software," or "a piece of malware" or "a piece of software."
