If you connect a machine running Office 2013 to the internet, you are a target for exploit chains (malicious Excel macros, RTF injection, etc.).
Outlook, Publisher, Access, Lync (later Skype for Business), and InfoPath. System Requirements pt office professional plus 2013 x64 vl.iso
use Office 2013 for daily banking, email (Outlook 2013 is highly vulnerable to modern phishing rendering engines), or handling sensitive client data. If you connect a machine running Office 2013