Well i must say that it's really nice and creative way to inject malicious, but still the "Victim" must have another malicious object on his machine to run this idea on,exactly like lots of other examples that relevant in other technological environments, not a big surprise.
The problem is that "everyone" need to "download" the blockchain in order to use Bitcoin,and then its like half way through for the "Hacker",the second half still has the same challenges that we know,how to interact with your "Victim" and give him the second peas of the cake..
Its not a big news at all,
Let the speculators play with the technology,i think its good for all of us...
There are a lot of ways to get specific information from the blockchain without having Bitcoin installed.