It is always a risk, but you will find out the moment you try to activate it. I had (incorrectly) assumed that you were referring to the subscription based version of Office 365.
I am not a MS fanboi, but, in time all software might be compromised. The more popular the software, the more likely it is that someone will try to hack it. For many years Apple was fortunate to dodge hacks through a principle called security through obscurity- why bother hacking an OS that hardly anyone uses? No operating system that has in internet access is "safe". Windows, MacOS, Linux, they are all hackable.