Critical Security Threat Notification

Yorb continues to proactively look for new and escalating security threats that could intrude on, damage, or infect your IT infrastructure and potentially in turn impact your business. This notice is a warning that the event listed below could constitute such a threat.

Please take the time to read this alert and our recommended actions. 

Threat Level: Critical

  • Critical: This is a very serious issue with a high possibility of a network compromise.
  • High: This is a serious issue with a possibility of compromise.
  • Medium: This is a serious issue but may not cause you immediate harm.

Name: Zero Day Microsoft Exchange Vulnerability
Type of Threat: System Compromise
Target: On-Premises Microsoft Exchange Servers 

Brief Description:

Microsoft has detected a nation-state exploiting a previously unknown vulnerability in Microsoft Exchange Server. Microsoft Exchange is commonly used to manage e-mail for businesses and ensure user integrity between on-premise servers and Office 365.

Who this affects:

Businesses that run their own Microsoft Exchange Server will be affected by this vulnerability. If you have a Managed Service Agreement with Yorb we have taken pro-active steps to apply the updates to your systems. If you do not have a Managed Service Agreement and are running a Microsoft Exchange Server please contact our Support Team ( so that we can discuss appropriate solutions.

Next steps:

The implementation of the security updates required to mitigate this vulnerability is quite involved. We are therefore taking a two-stage approach to the implementation. 

  1. Take steps to prevent the attack from hitting your servers by blocking access using your existing firewall. 
  2. Implement the required patches to your systems, this will require several system reboots. 

Due to the nature of the vulnerability and the fact that an active attack is already in progress we are proceeding with haste. Yorb will take every reasonable precaution to prevent interruption to your business, though some unexpected consequences maybe unavoidable. 

If you have any concerns or experience issues please make contact with our Support Centre ( to discuss further. 

Daniel Goymer

Technical Director