The FBI has recently warned that beginning in January 2017 that the IRS's Online Fraud Detection & Prevention (OFDP) observed an increase in phishing attacks requesting W-2 information.  The most common type of email impersonates an executive requesting W-2 information from a human resources employee.   The easiest indicator of phishing in these scenarios is that the IRS doesn't initiate contact with taxpayers by social media, text messages, nor email.