Thanks, Asyn. I used the “Restore Factory Defaults” command in the Troubleshooting menu, which reactivated the firewall. Should’ve mentioned that in my first post.

However, I’m still curious as to:

  1. Why this happened (is there a vulnerability affecting my comp that I haven’t noticed?), and

  2. Whether my comp was at risk for the 30 mins when the firewall was down.