Cybercriminals can steal money not just by putting malware on your machine, but by phishing attacks too. Phishing attacks don t just target online banking and e-payment systems, but almost any site which asks the user to input sensitive data. Sites run by national government agencies are a prime example as they often demand a wealth of personal information which goes far beyond a simple user name or account number + PIN. While filling in a tax return online might seem like a great way to save time and paper, it gives cybercriminals a great opportunity to scoop all your details at once.
Source: https://threatpost.com/malware-open-season-taxpayers-011110/73345/