A suspicious "Reminder" message

For a few weeks now, my mom has been getting 'reminders' about security updates on her 27" model 13,2 iMac. They look like reminder windows and appear in the upper right corner. One says that a security updated has been performed, another says a security update is required; see screenshot below. I have no idea what program is doing this. The fact that there nothing identifying which program is doing this worries me. Has anyone seen this before?

Thanks,
Jeff

It's Notification Center. Part of your Mac. Do what it says, it's important.

Chas,

Thanks for the quick reply. I am hesitant to question the experts, but I would appreciate it if you could go into a few specifics about why this is a benign reminder, as it seems pretty suspicious to me.

The only way to make the reminder go away is to accept the security update. This is suspicious to me since I have never seen any legitimate program fail to allow me to postpone or ignore any update.

I have never seen a legitimate program fail to identify which program it is. The only clue as to what is requiring the update is the small icon on the left.

I am also not getting this reminder on my 13,2 iMac. I keep it and my parents Mac configured as much the same as practical so I can help them with the simpler issues.

Again, thanks for the help.
Jeff

Apple has discovered a major security hole in the utility that updates the system clock from the internet. The risk is great, so Apple has pushed hard for people to update the software. I'm surprised that it's not already installed, as on my Apples, the update was applied without my intervention.

As chas_m said, just do it. Now.