Sort of. Theft isn't the primary motive, so I think it's inaccurate. A lot of what the fraudsters are (or will be) doing is transferring money from victims to innocent people. The real-life analogy I would use is going to a store and putting something in someone's bag without them noticing to test the store's security. That is arguably not theft, even though it's illegal.

I'd say the proper term is fraud. But I don't really like semantic arguments, so I'd say it's not a huge deal either way :)

edit: I should add, the reason I don't think it's stealing is because the money often gets returned; the illicit transfers can be reversed. When the real stealing will be going on the fraudsters will be taking lots of money and running.

edit2: I feel bad for even objecting, it's really not a big deal. 'Stealing money' is close enough to what's going on.