Maybe you have already seen this. I've been getting emails this tax season that go like this:
"Hi, I would like you to prepare my taxes this year -- here's a file with my information for you to look over".
There's a PDF attached. Which I can guarantee has executable code buried inside of it.
Another version of the email is simply "Hi - new client here, would like to set something up maybe on the weekend". I know the next email is going to be the "Here's my file of information" email.
Just be careful and don't ever open a PDF you don't know as coming from a trusted source.