While we have marked this issue as resolved we wanted to offer further updates (after banning M365 misconfigured instances from ExchangeDefender - they will still arrive in your SureSPAM folder and if you whitelist the domain they will pass on as normal)
We will have a new managed offering launching later in Summer 2021 to address these but for the moment we are dealing with multiple attack vectors and appreciate every .eml report we can get at https://support.ownwebnow.com
Update 02/24/2021 00:49 AM 11 days
As mentioned in the previous update, we have been blocking a lot of the new exploited IP addresses. One thing they all seem to have in common is that they are abusing organizations that match these two criteria:
You will see these headers in many SPAM pieces.
For the time being, we will classify Microsoft email from these open relays as SPAM far more aggressively. It will not impact normal traffic from Microsoft, but if they are an open relay those messages.
Update 02/23/2021 17:13 PM 12 days
We have been monitoring an explosion of new compromised systems that are suddenly broadcasting large amounts of SPAM. These IP addresses have never been used for SPAM activity before (and clearly belong to legitimate companies) and we are blocking them as fast as they show up on our firewalls. Here are some of the top subjects:
Restore Your Gut Health As You Sleep with Peptiva
go-peakbusinessfinancing.com $COMPANY // Reach the Peak
Green Veggie INFLAMES Diabetes Type 2 (Avoid)
Worried about your identity? Try ?ife?ock free!
African Priest Helps White Man Gain 6 Inches
White Man Offers Wife To African Priest For Member Growth Secret
2021 is Here - Big D Paving Co Start of Year Funding Deals
While most of these are getting picked off by our SPAM filtering natively, we are actively mapping out this new botnet and blocking it aggressively.
If you have users with SureSPAM policy set to "Deliver" you should immediately change it to Quarantine/Store so your users aren't being annoyed with pieces that are coming from IP addresses with good IP reputation.