All WSU email addresses are publicly available on WSU's web site. Since we are a state funded institution, all directory information is available to the public. It is possible that a scraper service trolled WSU's directory for email addresses.
You are always welcome
to directly forward emails you receive that are SPAM to abuse@wsu.edu. The emails will go
directly to the security team. If deemed malicious, they will take steps to
block the sender. The header information is critical to help them determine the
source of the emails.
There are a couple steps you can take to insulate yourself in the future from these emails. You can contact your local it support to help you setup a filter to block the emails.
You can also block a sender using O365, which will divert unwanted emails to your junk folder: