Here is a blog covering some more in depth details.

https://www.huntress.com/blog/rapid-response-mass-exploitation-of-on-prem-exchange-servers

Thank you,

Kevin McCormick

From: NANOG <nanog-bounces+kmccormick=mdtc.net@nanog.org> On Behalf Of Scott Morizot
Sent: Friday, March 5, 2021 5:02 PM
To: Eric Kuhnke <eric.kuhnke@gmail.com>
Cc: nanog@nanog.org list <nanog@nanog.org>
Subject: Re: Microsoft Exchange zero day

On Fri, Mar 5, 2021 at 4:26 PM Eric Kuhnke <eric.kuhnke@gmail.com> wrote:

ISPs/NSPs with customers running self hosted or on-premises Exchange may want to be aware of this.

https://krebsonsecurity.com/2021/03/at-least-30000-u-s-organizations-newly-hacked-via-holes-in-microsofts-email-software/

https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/

Yes, and CISA released an alert and an emergency directive.

https://us-cert.cisa.gov/ncas/current-activity/2021/03/03/cisa-issues-emergency-directive-and-alert-microsoft-exchange